You're sending legitimate emails to your customers, but Gmail is showing them a big orange warning: "We can't verify that this email came from the sender so it might not be safe to respond to it."<img class="rounded-2xl border border-primaryBorder mx-auto" src="https://dqy38fnwh4fqs.cloudfront.net/blog/blog-content-image-5cf0637a-7f5d-4b67-839e-e65bf98b9ecc.webp">This sucks. Your emails aren't spam. You're not phishing anyone. But to Gmail and other inbox providers, they look suspicious.If you're using an email service like AutoSend, Amazon SES, SendGrid, Postmark, or Mailgun to send emails, there's a good chance your DNS records are misconfigured. Specifically, something called DMARC alignment.Here's what's actually happening and how to fix it.<h2>What's Really Going On</h2>When your email service sends an email on your behalf, there's a behind-the-scenes address called the Return-Path. This is different from the From address your customers see.For example, when you send an email from <code>hello@yourcompany.com</code>, your email service might use <code>bounces@mail.yourcompany.com</code> as the Return-Path. This is normal. Email services do this to handle bounces and track delivery.The problem happens when you have something called "strict alignment" turned on in your DMARC settings. With strict alignment, these two addresses need to match exactly. But they don't because one uses a subdomain. So Gmail sees the mismatch and freaks out.This is the issue most people hit when using email services. The fix is simple once you know what to look for.<h2>Understanding the Three Email Records</h2>Think of email authentication like a security system with three checks. Each one verifies something different about your email.<h3>SPF: The Authorized Sender List</h3><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/spf-sender-policy-framework">SPF</a> is a list in your DNS that says "these mail servers are allowed to send emails for my domain." When you use an email service to send emails, you need to add them to this list.The most common mistake is using <code>-all</code> at the end of your SPF record instead of <code>~all</code>. The <code>-all</code> means "reject anything not on this list" which is too strict. If your email service isn't properly listed, your emails get rejected. Use <code>~all</code> instead, which means "mark as suspicious" rather than outright rejection.Another mistake is adding your email service to a subdomain but forgetting to add it to your main domain. If you send from <code>hello@yourcompany.com</code>, make sure your main domain's SPF record includes your email service.Example SPF records:If you're using Google Workspace and AutoSend:<pre><code>v=spf1 include:_spf.google.com include:amazonses.com ~all</code></pre>If you're using Google Workspace and SendGrid:<pre><code>v=spf1 include:_spf.google.com include:sendgrid.net ~all</code></pre>If you're using Microsoft 365 and Postmark:<pre><code>v=spf1 include:spf.protection.outlook.com include:spf.mtasv.net ~all</code></pre>The pattern is always: <code>v=spf1</code> followed by domains, ending with <code>~all</code>.<h3>DKIM: The Tamper-Proof Seal</h3><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/dkim-domainkeys-identified-mail">DKIM</a> is a digital signature that proves your email hasn't been modified in transit. Your email service signs the email with a private key, and receivers check it with a public key in your DNS.The issue happens when you have old DKIM keys from a previous email service but no keys from your current one. Or worse, empty DKIM records that say "we sign emails" but don't provide a way to verify them.Make sure you have DKIM keys from your current email service in your DNS. Your email service dashboard will show you what records to add.Example DKIM records:Most email services give you TXT records to add. For AutoSend, you might add:<pre><code>Record name: autosend._domainkey
Record type: TXT
Record value: p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBg...</code></pre>For SendGrid, it might look like:<pre><code>Record name: s1._domainkey.yourcompany.com
Record type: CNAME
Record value: s1.domainkey.u12345.wl.sendgrid.net</code></pre>For Google Workspace, you'll get a TXT record:<pre><code>Record name: google._domainkey.yourcompany.com
Record type: TXT
Record value: v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBA...</code></pre>Your email service will provide the exact values. Just copy them into your DNS.<h3>DMARC: The Policy That Ties It Together</h3><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/dmarc-domain-based-message-authentication-reporting-conformance">DMARC</a> tells email receivers what to do if SPF or DKIM checks fail. But it also does something tricky called "alignment checking."There are two types of alignment: strict and relaxed. Strict alignment means the domains have to match exactly. So <code>hello@yourcompany.com</code> and <code>bounces@mail.yourcompany.com</code> don't match because one uses a subdomain.Relaxed alignment is smarter. It understands that <code>mail.yourcompany.com</code> and <code>yourcompany.com</code> are part of the same organization, so it counts them as matching.Almost every email service uses subdomains for technical stuff like bounces. This is why relaxed alignment is the standard, and why strict alignment breaks things.Example DMARC records:A good starting DMARC record with relaxed alignment:<pre><code>Record name: _dmarc.yourcompany.com
Record type: TXT
Record value: v=DMARC1; p=none; rua=mailto:dmarc@yourcompany.com; adkim=r; aspf=r</code></pre>Once you've verified everything works, change to quarantine:<pre><code>v=DMARC1; p=quarantine; rua=mailto:dmarc@yourcompany.com; adkim=r; aspf=r; pct=100</code></pre>Breaking down what each part means:<ul><li><code>v=DMARC1</code> - DMARC version</li><li><code>p=quarantine</code> - Put suspicious emails in spam (use <code>p=none</code> while testing)</li><li><code>rua=mailto:dmarc@yourcompany.com</code> - Where to send reports</li><li><code>adkim=r</code> - Relaxed DKIM alignment (this is the important one)</li><li><code>aspf=r</code> - Relaxed SPF alignment (also important)</li><li><code>pct=100</code> - Apply policy to 100% of emails</li></ul>The key parts are <code>adkim=r</code> and <code>aspf=r</code>. These need to be set to <code>r</code> (relaxed) not <code>s</code> (strict).<h2>How to Figure Out What's Wrong</h2>First, check your actual DNS records. Don't trust what your DNS service provider's dashboard says. Use a command line tool or an online DNS checker to see what's actually there. Look up your domain's TXT records and your DMARC records.Common things you'll find: multiple DMARC records (you can only have one), strict alignment enabled when it should be relaxed, or your email service missing from your main domain's SPF record.Next, send yourself a test email and look at the raw headers. In Gmail, click the three dots and choose "Show original." Look for the Return-Path and Authentication-Results headers. This will show you exactly what's failing.<img class="rounded-2xl border border-primaryBorder mx-auto" src="https://dqy38fnwh4fqs.cloudfront.net/blog/blog-content-image-723cc788-05ab-49a5-b736-974ae17bb1ff.webp">If you've set up DMARC reports (the <code>rua=</code> part of your DMARC record), you'll get XML reports showing authentication failures. They're ugly to read but they tell you exactly what's going wrong. Just give it to Claude or ChatGPT for interpretation. <h2>The Fix</h2>The fix usually involves three changes.Change your DMARC to relaxed alignment. Find your DMARC record and look for <code>adkim=s; aspf=s</code>. Change both of those to <code>r</code> instead of <code>s</code>. This tells email receivers that subdomains are okay as long as they're part of the same organization.Add your email service to your main domain's SPF record. If you're using AutoSend, add <code>include:amazonses.com</code> to your SPF record. For SendGrid, add <code>include:sendgrid.net</code>. For Postmark, add <code>include:spf.mtasv.net</code>. Your email service's documentation will tell you what to add.Change <code>-all</code> to <code>~all</code> in your SPF record. This changes from "reject" to "mark as suspicious" which is safer and more forgiving if something goes wrong.That's it. No content changes, no IP warming, no deliverability magic. Just three DNS updates and your emails will stop showing warnings.<h2>Quick Checklist</h2>If you're seeing warnings, here's what to check. Is your email service included in your main domain's SPF record? Are you using <code>~all</code> at the end of that record instead of <code>-all</code>? Do you have DKIM keys from your current email service in your DNS? Do you have only one DMARC record with relaxed alignment?Send yourself a test email and check the headers in Gmail (three dots, then Show original). Make sure SPF, DKIM, and DMARC all show as passing.<img class="rounded-2xl border border-primaryBorder mx-auto" src="https://dqy38fnwh4fqs.cloudfront.net/blog/blog-content-image-ef3b7beb-05cd-4e42-a69f-f56ed52c3474.webp"><h2>Why This Matters Now</h2>Email authentication has been around for years, but Gmail and Yahoo made their requirements stricter in 2024. What used to work fine might now trigger warnings.That orange warning banner kills trust. But it's fixable with DNS records. Once you understand what SPF, DKIM, and DMARC actually do, fixing them is straightforward.Think of it this way: SPF says who can send emails for you. DKIM proves the email hasn't been tampered with. DMARC says what to do if those checks fail. Get those three working with relaxed alignment and you're done.<h2>One More Thing</h2>Email authentication shouldn't be this confusing. The problem is that most email services just give you DNS records to copy without explaining what they do or why they matter.If you're stuck on this, check your email service's documentation for their SPF and DKIM setup instructions. Most have a support article that walks through it step by step.And if you're still seeing warnings after making these changes, reach out to your email service's support. They can usually spot the issue in a few minutes since they've seen it hundreds of times before.The key is understanding that strict alignment is what breaks things for most people. Switch to relaxed alignment and make sure your email service is properly authorized in your DNS. That solves it 90% of the time.<hr>Bonus tip: Disable open rate tracking for your emails if you're using a new domain to send emails.

You're sending legitimate emails to your customers, but Gmail is showing them a big orange warning: "We can't verify that this email came from the sender so it might not be safe to respond to it."This sucks. Your emails aren't spam. You're not phishing anyone. But to Gmail and other inbox providers, they look suspicious.If you're using an email service like AutoSend, Amazon SES, SendGrid, Postmark, or Mailgun to send emails, there's a good chance your DNS records are misconfigured. Specifically, something called DMARC alignment.Here's what's actually happening and how to fix it.What's Really Going OnWhen your email service sends an email on your behalf, there's a behind-the-scenes address called the Return-Path. This is different from the From address your customers see.For example, when you send an email from hello@yourcompany.com, your email service might use bounces@mail.yourcompany.com as the Return-Path. This is normal. Email services do this to handle bounces and track delivery.The problem happens when you have something called "strict alignment" turned on in your DMARC settings. With strict alignment, these two addresses need to match exactly. But they don't because one uses a subdomain. So Gmail sees the mismatch and freaks out.This is the issue most people hit when using email services. The fix is simple once you know what to look for.Understanding the Three Email RecordsThink of email authentication like a security system with three checks. Each one verifies something different about your email.SPF: The Authorized Sender ListSPF is a list in your DNS that says "these mail servers are allowed to send emails for my domain." When you use an email service to send emails, you need to add them to this list.The most common mistake is using -all at the end of your SPF record instead of ~all. The -all means "reject anything not on this list" which is too strict. If your email service isn't properly listed, your emails get rejected. Use ~all instead, which means "mark as suspicious" rather than outright rejection.Another mistake is adding your email service to a subdomain but forgetting to add it to your main domain. If you send from hello@yourcompany.com, make sure your main domain's SPF record includes your email service.Example SPF records:If you're using Google Workspace and AutoSend:v=spf1 include:_spf.google.com include:amazonses.com ~allIf you're using Google Workspace and SendGrid:v=spf1 include:_spf.google.com include:sendgrid.net ~allIf you're using Microsoft 365 and Postmark:v=spf1 include:spf.protection.outlook.com include:spf.mtasv.net ~allThe pattern is always: v=spf1 followed by domains, ending with ~all.DKIM: The Tamper-Proof SealDKIM is a digital signature that proves your email hasn't been modified in transit. Your email service signs the email with a private key, and receivers check it with a public key in your DNS.The issue happens when you have old DKIM keys from a previous email service but no keys from your current one. Or worse, empty DKIM records that say "we sign emails" but don't provide a way to verify them.Make sure you have DKIM keys from your current email service in your DNS. Your email service dashboard will show you what records to add.Example DKIM records:Most email services give you TXT records to add. For AutoSend, you might add:Record name: autosend._domainkey
Record type: TXT
Record value: p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBg...For SendGrid, it might look like:Record name: s1._domainkey.yourcompany.com
Record type: CNAME
Record value: s1.domainkey.u12345.wl.sendgrid.netFor Google Workspace, you'll get a TXT record:Record name: google._domainkey.yourcompany.com
Record type: TXT
Record value: v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBA...Your email service will provide the exact values. Just copy them into your DNS.DMARC: The Policy That Ties It TogetherDMARC tells email receivers what to do if SPF or DKIM checks fail. But it also does something tricky called "alignment checking."There are two types of alignment: strict and relaxed. Strict alignment means the domains have to match exactly. So hello@yourcompany.com and bounces@mail.yourcompany.com don't match because one uses a subdomain.Relaxed alignment is smarter. It understands that mail.yourcompany.com and yourcompany.com are part of the same organization, so it counts them as matching.Almost every email service uses subdomains for technical stuff like bounces. This is why relaxed alignment is the standard, and why strict alignment breaks things.Example DMARC records:A good starting DMARC record with relaxed alignment:Record name: _dmarc.yourcompany.com
Record type: TXT
Record value: v=DMARC1; p=none; rua=mailto:dmarc@yourcompany.com; adkim=r; aspf=rOnce you've verified everything works, change to quarantine:v=DMARC1; p=quarantine; rua=mailto:dmarc@yourcompany.com; adkim=r; aspf=r; pct=100Breaking down what each part means:v=DMARC1 - DMARC versionp=quarantine - Put suspicious emails in spam (use p=none while testing)rua=mailto:dmarc@yourcompany.com - Where to send reportsadkim=r - Relaxed DKIM alignment (this is the important one)aspf=r - Relaxed SPF alignment (also important)pct=100 - Apply policy to 100% of emailsThe key parts are adkim=r and aspf=r. These need to be set to r (relaxed) not s (strict).How to Figure Out What's WrongFirst, check your actual DNS records. Don't trust what your DNS service provider's dashboard says. Use a command line tool or an online DNS checker to see what's actually there. Look up your domain's TXT records and your DMARC records.Common things you'll find: multiple DMARC records (you can only have one), strict alignment enabled when it should be relaxed, or your email service missing from your main domain's SPF record.Next, send yourself a test email and look at the raw headers. In Gmail, click the three dots and choose "Show original." Look for the Return-Path and Authentication-Results headers. This will show you exactly what's failing.If you've set up DMARC reports (the rua= part of your DMARC record), you'll get XML reports showing authentication failures. They're ugly to read but they tell you exactly what's going wrong. Just give it to Claude or ChatGPT for interpretation. The FixThe fix usually involves three changes.Change your DMARC to relaxed alignment. Find your DMARC record and look for adkim=s; aspf=s. Change both of those to r instead of s. This tells email receivers that subdomains are okay as long as they're part of the same organization.Add your email service to your main domain's SPF record. If you're using AutoSend, add include:amazonses.com to your SPF record. For SendGrid, add include:sendgrid.net. For Postmark, add include:spf.mtasv.net. Your email service's documentation will tell you what to add.Change -all to ~all in your SPF record. This changes from "reject" to "mark as suspicious" which is safer and more forgiving if something goes wrong.That's it. No content changes, no IP warming, no deliverability magic. Just three DNS updates and your emails will stop showing warnings.Quick ChecklistIf you're seeing warnings, here's what to check. Is your email service included in your main domain's SPF record? Are you using ~all at the end of that record instead of -all? Do you have DKIM keys from your current email service in your DNS? Do you have only one DMARC record with relaxed alignment?Send yourself a test email and check the headers in Gmail (three dots, then Show original). Make sure SPF, DKIM, and DMARC all show as passing.Why This Matters NowEmail authentication has been around for years, but Gmail and Yahoo made their requirements stricter in 2024. What used to work fine might now trigger warnings.That orange warning banner kills trust. But it's fixable with DNS records. Once you understand what SPF, DKIM, and DMARC actually do, fixing them is straightforward.Think of it this way: SPF says who can send emails for you. DKIM proves the email hasn't been tampered with. DMARC says what to do if those checks fail. Get those three working with relaxed alignment and you're done.One More ThingEmail authentication shouldn't be this confusing. The problem is that most email services just give you DNS records to copy without explaining what they do or why they matter.If you're stuck on this, check your email service's documentation for their SPF and DKIM setup instructions. Most have a support article that walks through it step by step.And if you're still seeing warnings after making these changes, reach out to your email service's support. They can usually spot the issue in a few minutes since they've seen it hundreds of times before.The key is understanding that strict alignment is what breaks things for most people. Switch to relaxed alignment and make sure your email service is properly authorized in your DNS. That solves it 90% of the time.Bonus tip: Disable open rate tracking for your emails if you're using a new domain to send emails.

Gmail marking your emails as suspicious? Fix DMARC strict alignment with this SPF, DKIM, and DMARC DNS configuration guide.

Why Gmail Says Your Emails "Appear Suspicious" (And How to Fix It)

You're staring at your email dashboard. Open rate: 24%. Click rate: 3.2%. Unsubscribe rate: 0.8%.Are those numbers good? Bad? Should you change something, or keep doing what you're doing?Most email analytics dashboards throw numbers at you with zero context. You see percentages and graphs, but no explanation of what they actually mean or what to do about them. Even worse, the metrics people obsess over most (like open rates) are increasingly unreliable.Here's what actually matters: complaint rates tell you if people hate your emails. Bounce rates show list quality and technical issues. Click-through rates reveal genuine engagement. Unsubscribe patterns indicate content fit. And when you read these metrics together instead of in isolation, they tell you exactly what's working and what needs to fix.This guide breaks down each metric that actually impacts your email performance. For each one, you'll learn what it measures, what healthy benchmarks look like, what trends mean, and what action to take. By the end, you'll know how to read your email analytics like a pro and make data-driven improvements.Let's start with why everyone's favorite metric is fundamentally broken.<h2>Why Open Rates Don't Mean What They Used To</h2>Open rates used to be simple: someone opened your email, a tiny tracking pixel loaded, and you counted it as an open.Then Apple Mail Privacy Protection came along. Now when Apple Mail users download emails, Apple's servers pre-load all images and tracking pixels automatically, whether the person actually opened the email or not. This happens for roughly 40-50% of email users, and that percentage keeps growing.The result: your open rates are inflated with phantom opens from people who never actually saw your email. A 35% open rate might really be 20%. You have no way to know which opens are real and which are Apple's servers.Open rates aren't useless, but they're no longer reliable as a primary metric. You can still track trends (if your open rate suddenly drops from 30% to 15%, something's wrong), but don't make decisions based on absolute numbers or small changes.Here's what to track instead.<h2>Complaint Rate: Your Most Critical Metric</h2>Complaint rate is the percentage of recipients who marked your email as spam. This is the single most important number in your analytics because it directly destroys your sender reputation.Email service providers watch this metric obsessively. If your complaint rate goes above 0.1% (1 complaint per 1,000 emails), you're in dangerous territory. Above 0.3%, you're likely to get throttled or blacklisted.Healthy benchmark: Under 0.1% Warning zone: 0.1% - 0.3% Critical: Above 0.3%What trends mean:A sudden spike in complaints usually means something specific went wrong. You sent to an old list, your subject line was misleading, you emailed people who unsubscribed, or your content was completely off-brand from what people expected.Gradual increases mean you're slowly losing relevance with your audience. Your content isn't matching what people signed up for, or you're sending too frequently.What to do:If you see a spike, immediately identify what was different about that send. Different subject line? New list segment? Content change? Stop that immediately.If complaints are gradually rising, segment your list and look at who's complaining. Are they new subscribers or old? Did they come from a specific signup source? Are certain email types getting more complaints than others? This tells you where the mismatch is.Never ignore complaints. Every person who hits the spam button is telling both you and their email provider that you're unwanted. Fix it fast.<hr><h2>Bounce Rate: List Quality and Technical Health</h2>Bounces happen when your email can't be delivered. There are two types, and they mean very different things.Hard bounces are permanent failures. The email address doesn't exist, the domain is invalid, or the recipient's server has permanently rejected you. These addresses will never work.Soft bounces are temporary. The recipient's inbox is full, their server is down, or the email was too large. These might work if you try again later.Healthy benchmarks: Hard bounce rate: Under 2% Soft bounce rate: Under 5%What trends mean:High hard bounce rates indicate list quality problems. You're either collecting email addresses incorrectly, buying lists (don't), or haven't cleaned your list in forever. Hard bounces also include spam traps, which will destroy your reputation.Rising soft bounce rates usually mean technical issues. Your emails might be too large, your content triggers receiving server filters, or you're hitting rate limits.What to do:Remove hard bounces from your list immediately. There's no point sending to addresses that don't exist, and it hurts your sender reputation every time you try.For soft bounces, AutoSend will retry a few times before giving up. If an address soft bounces repeatedly over weeks, treat it like a hard bounce and remove it.If your hard bounce rate is above 4%, you have a serious list quality problem. Stop sending, figure out where bad addresses are coming from, and clean your list. At AutoSend, we automatically suppress hard bounces so you don't keep hitting dead addresses, but you need to fix the source of the problem.<h2>Click-Through Rate: Actual Engagement</h2>Click-through rate (CTR) is the percentage of recipients who clicked a link in your email. Unlike open rates, clicks are reliable. Someone either clicked or they didn't.This is your best measure of genuine engagement. It tells you if your content is interesting enough to act on, if your calls-to-action are working, and if you're reaching people who actually care.Healthy benchmarks: Transactional emails: 10-20% Marketing emails: 2-5% Cold outreach: 1-3%These vary wildly by industry and email type, so track your own baseline and measure against that.What trends mean:Declining CTR means your content is becoming less relevant. Your subject lines might be misleading (high opens, low clicks), your CTAs are unclear, or you're sending to disengaged subscribers.High opens with low clicks specifically means a mismatch between subject line and content. People open expecting one thing and get something else.Low opens with high clicks means your subject lines are weak but your content is strong. The people who do open are engaged.What to do:If clicks are declining across all emails, you have a content problem. Survey your audience, test different formats, or segment more carefully to match content to interests.If specific emails have low CTR, look at the email itself. Is the CTA clear? Are you asking too much? Is there too much text before the link? Test different approaches.Track which links get clicked. If you have five links but everyone only clicks one, that tells you what people actually care about. Double down on that.<hr><h2>Unsubscribe Rate: Signal vs Noise</h2>Unsubscribe rate is the percentage of recipients who opted out. This metric confuses people because it's not inherently bad.Some unsubscribes are healthy. People's needs change, they no longer need your product, or they signed up for one thing and you're sending another. It's better they unsubscribe than mark you as spam.Healthy benchmark: 0.2% - 0.5% per sendWhat trends mean:A sudden spike in unsubscribes (above 1%) means something was wrong with that specific email. Misleading subject line, content completely off-brand, wrong audience segment, or you accidentally sent to an old/inactive list.Gradual increases mean slow relevance decay. You're losing alignment with your audience's interests.Very low unsubscribe rates (under 0.1%) combined with low engagement might mean your unsubscribe link is hard to find, which is worse. People will just mark you as spam instead.What to do:If you see a spike, figure out what was different about that send, just like with complaints. But don't panic over normal unsubscribe rates. Losing people who aren't interested is good for your engagement metrics and sender reputation.If unsubscribes are trending up slowly, segment your list and see who's leaving. New subscribers? Old ones? Specific signup sources? This tells you where the mismatch is happening.The worst scenario is high unsubscribes AND high complaints. That means people are so annoyed they're taking two different actions to stop hearing from you. Fix this immediately.<hr><h2>Conversion Rate: The Bottom Line</h2>Conversion rate measures how many recipients took the action you actually wanted. Made a purchase, signed up for something, downloaded a resource, replied to your email, whatever your goal was.This is the metric that matters to your business, but it's also the hardest to track because it requires connecting email clicks to actions taken elsewhere.Healthy benchmarks: These vary so wildly by industry, email type, and goal that generic benchmarks are useless. Track your own baseline.What trends mean:Low conversion despite high CTR means your landing page or offer is the problem, not your email. People are interested enough to click but something on the other side isn't working.Low conversion with low CTR means the email itself isn't compelling enough to get people to take the first step.What to do:Make sure you're actually tracking conversions. Use UTM parameters, conversion pixels, or unique tracking links so you can attribute actions back to specific emails.If clicks are high but conversions are low, fix what happens after the click. Test your landing page, simplify the conversion path, or adjust your offer.If both clicks and conversions are low, the problem is in the email. Test different subject lines, content formats, and CTAs.<hr><h2>Time-to-Open and Time-to-Click Patterns</h2>Most people don't think about timing, but when people open and click tells you a lot.If 80% of your opens happen in the first hour after sending, your subject line is strong and your audience is engaged. If opens trickle in over days, you're hitting inactive users or your content isn't time-sensitive enough to prioritize.Click timing is even more interesting. Fast clicks (within minutes of opening) suggest impulse actions or high-intent content. Delayed clicks might mean people are reading carefully or coming back to something they saved.What to do:Look at when your emails get the most engagement and send during those windows. If your audience opens emails at 8am on Tuesdays, don't send at 3pm on Fridays.For transactional emails, fast open times are critical. If it takes hours for someone to see their password reset, that's a problem. Check if your sending is delayed or if emails are getting filtered.Track how timing correlates with conversions. Sometimes the people who click immediately convert poorly (impulse, not ready), while delayed clicks convert better (thoughtful consideration). This changes how you optimize.<hr><h2>Re-Engagement Patterns</h2>This isn't a single metric but a pattern to watch: how often do the same people engage with your emails over time?Some subscribers open everything you send. Others open once every few months. Some clicked five emails in a row, then nothing for weeks. These patterns tell you who's genuinely engaged versus who's passively on your list.What to track:Segment your list by engagement recency. Who opened in the last 7 days? 30 days? 90 days? Never?Watch for engagement decay. If someone goes from opening every email to opening every third email to not opening at all, they're slowly churning. Catch them before they're completely disengaged.What to do:Create win-back campaigns for people who haven't engaged in 60-90 days. Ask if they still want to hear from you, offer to change email frequency, or give them a compelling reason to re-engage.For your most engaged subscribers, consider sending them more content or exclusive offers. These are your best customers, don't ignore them by treating everyone the same.Regularly clean your list by removing people who haven't engaged in 6+ months. They're hurting your metrics and costing you money with no benefit.<hr><h2>How to Read Metrics Together</h2>Individual metrics are useful, but reading them in combination tells you what's actually happening.High opens, low clicks: Subject line works but content doesn't deliver. Your emails promise one thing and deliver another, or your CTAs are weak.Low opens, high clicks: Subject lines are terrible but content is great. The people who do open are highly engaged. Improve your subject lines.High clicks, low conversions: Email is working, but your landing page, offer, or next step is broken. Fix what happens after the click.Rising unsubscribes, stable complaints: People are politely leaving instead of marking you spam. Content mismatch, but you're making it easy to opt out. Good.Rising complaints, rising unsubscribes: People are so frustrated they're taking multiple actions to stop hearing from you. Major content problem or you're emailing the wrong people.High bounces, high complaints: List quality disaster. You're sending to bad addresses and the ones that do exist don't want your emails. Stop immediately and clean your list.Declining engagement across all metrics: General relevance decay. Your content is becoming less interesting, you're sending too frequently, or your audience is changing and you're not adapting.Look at your metrics together every week, not just when something goes wrong. Patterns emerge over time that aren't visible in single sends.<hr><h2>Vanity Metrics That Don't Actually Matter</h2>Some metrics look impressive but tell you nothing useful:Total subscribers: Meaningless without engagement rates. 100,000 subscribers with 1% engagement is worse than 10,000 with 20% engagement. Quality over quantity always.Email sent count: Sending more emails doesn't mean anything if they're not being read or acted on. Don't celebrate volume, celebrate engagement.List growth rate: Growing fast is only good if you're growing with engaged, relevant subscribers. Adding 1,000 people who never open your emails hurts more than it helps.Delivery rate: This just means the email technically arrived at a server somewhere. It doesn't mean it hit the inbox versus the spam folder. Focus on engagement, not technical delivery.Stop tracking these or at least stop making decisions based on them. They make you feel good without indicating real email health.<hr><h2>Start With the Metrics That Impact Deliverability</h2>You don't need to track everything at once. Start with the metrics that directly impact your sender reputation: complaint rate, bounce rate, and engagement patterns.Get those right and you'll land in inboxes consistently. Then layer in conversion tracking and more sophisticated analysis as you scale.The goal isn't to obsess over numbers. It's to understand what your audience is telling you through their behavior and respond accordingly. Low engagement means your content isn't relevant. High complaints mean you're annoying people. Rising bounces mean your list is degrading.Fix the signals, and the numbers will improve naturally.

You're staring at your email dashboard. Open rate: 24%. Click rate: 3.2%. Unsubscribe rate: 0.8%.Are those numbers good? Bad? Should you change something, or keep doing what you're doing?Most email analytics dashboards throw numbers at you with zero context. You see percentages and graphs, but no explanation of what they actually mean or what to do about them. Even worse, the metrics people obsess over most (like open rates) are increasingly unreliable.Here's what actually matters: complaint rates tell you if people hate your emails. Bounce rates show list quality and technical issues. Click-through rates reveal genuine engagement. Unsubscribe patterns indicate content fit. And when you read these metrics together instead of in isolation, they tell you exactly what's working and what needs to fix.This guide breaks down each metric that actually impacts your email performance. For each one, you'll learn what it measures, what healthy benchmarks look like, what trends mean, and what action to take. By the end, you'll know how to read your email analytics like a pro and make data-driven improvements.Let's start with why everyone's favorite metric is fundamentally broken.Why Open Rates Don't Mean What They Used ToOpen rates used to be simple: someone opened your email, a tiny tracking pixel loaded, and you counted it as an open.Then Apple Mail Privacy Protection came along. Now when Apple Mail users download emails, Apple's servers pre-load all images and tracking pixels automatically, whether the person actually opened the email or not. This happens for roughly 40-50% of email users, and that percentage keeps growing.The result: your open rates are inflated with phantom opens from people who never actually saw your email. A 35% open rate might really be 20%. You have no way to know which opens are real and which are Apple's servers.Open rates aren't useless, but they're no longer reliable as a primary metric. You can still track trends (if your open rate suddenly drops from 30% to 15%, something's wrong), but don't make decisions based on absolute numbers or small changes.Here's what to track instead.Complaint Rate: Your Most Critical MetricComplaint rate is the percentage of recipients who marked your email as spam. This is the single most important number in your analytics because it directly destroys your sender reputation.Email service providers watch this metric obsessively. If your complaint rate goes above 0.1% (1 complaint per 1,000 emails), you're in dangerous territory. Above 0.3%, you're likely to get throttled or blacklisted.Healthy benchmark: Under 0.1%Warning zone: 0.1% - 0.3%Critical: Above 0.3%What trends mean:A sudden spike in complaints usually means something specific went wrong. You sent to an old list, your subject line was misleading, you emailed people who unsubscribed, or your content was completely off-brand from what people expected.Gradual increases mean you're slowly losing relevance with your audience. Your content isn't matching what people signed up for, or you're sending too frequently.What to do:If you see a spike, immediately identify what was different about that send. Different subject line? New list segment? Content change? Stop that immediately.If complaints are gradually rising, segment your list and look at who's complaining. Are they new subscribers or old? Did they come from a specific signup source? Are certain email types getting more complaints than others? This tells you where the mismatch is.Never ignore complaints. Every person who hits the spam button is telling both you and their email provider that you're unwanted. Fix it fast.Bounce Rate: List Quality and Technical HealthBounces happen when your email can't be delivered. There are two types, and they mean very different things.Hard bounces are permanent failures. The email address doesn't exist, the domain is invalid, or the recipient's server has permanently rejected you. These addresses will never work.Soft bounces are temporary. The recipient's inbox is full, their server is down, or the email was too large. These might work if you try again later.Healthy benchmarks:Hard bounce rate: Under 2%Soft bounce rate: Under 5%What trends mean:High hard bounce rates indicate list quality problems. You're either collecting email addresses incorrectly, buying lists (don't), or haven't cleaned your list in forever. Hard bounces also include spam traps, which will destroy your reputation.Rising soft bounce rates usually mean technical issues. Your emails might be too large, your content triggers receiving server filters, or you're hitting rate limits.What to do:Remove hard bounces from your list immediately. There's no point sending to addresses that don't exist, and it hurts your sender reputation every time you try.For soft bounces, AutoSend will retry a few times before giving up. If an address soft bounces repeatedly over weeks, treat it like a hard bounce and remove it.If your hard bounce rate is above 4%, you have a serious list quality problem. Stop sending, figure out where bad addresses are coming from, and clean your list. At AutoSend, we automatically suppress hard bounces so you don't keep hitting dead addresses, but you need to fix the source of the problem.Click-Through Rate: Actual EngagementClick-through rate (CTR) is the percentage of recipients who clicked a link in your email. Unlike open rates, clicks are reliable. Someone either clicked or they didn't.This is your best measure of genuine engagement. It tells you if your content is interesting enough to act on, if your calls-to-action are working, and if you're reaching people who actually care.Healthy benchmarks:Transactional emails: 10-20%Marketing emails: 2-5%Cold outreach: 1-3%These vary wildly by industry and email type, so track your own baseline and measure against that.What trends mean:Declining CTR means your content is becoming less relevant. Your subject lines might be misleading (high opens, low clicks), your CTAs are unclear, or you're sending to disengaged subscribers.High opens with low clicks specifically means a mismatch between subject line and content. People open expecting one thing and get something else.Low opens with high clicks means your subject lines are weak but your content is strong. The people who do open are engaged.What to do:If clicks are declining across all emails, you have a content problem. Survey your audience, test different formats, or segment more carefully to match content to interests.If specific emails have low CTR, look at the email itself. Is the CTA clear? Are you asking too much? Is there too much text before the link? Test different approaches.Track which links get clicked. If you have five links but everyone only clicks one, that tells you what people actually care about. Double down on that.Unsubscribe Rate: Signal vs NoiseUnsubscribe rate is the percentage of recipients who opted out. This metric confuses people because it's not inherently bad.Some unsubscribes are healthy. People's needs change, they no longer need your product, or they signed up for one thing and you're sending another. It's better they unsubscribe than mark you as spam.Healthy benchmark: 0.2% - 0.5% per sendWhat trends mean:A sudden spike in unsubscribes (above 1%) means something was wrong with that specific email. Misleading subject line, content completely off-brand, wrong audience segment, or you accidentally sent to an old/inactive list.Gradual increases mean slow relevance decay. You're losing alignment with your audience's interests.Very low unsubscribe rates (under 0.1%) combined with low engagement might mean your unsubscribe link is hard to find, which is worse. People will just mark you as spam instead.What to do:If you see a spike, figure out what was different about that send, just like with complaints. But don't panic over normal unsubscribe rates. Losing people who aren't interested is good for your engagement metrics and sender reputation.If unsubscribes are trending up slowly, segment your list and see who's leaving. New subscribers? Old ones? Specific signup sources? This tells you where the mismatch is happening.The worst scenario is high unsubscribes AND high complaints. That means people are so annoyed they're taking two different actions to stop hearing from you. Fix this immediately.Conversion Rate: The Bottom LineConversion rate measures how many recipients took the action you actually wanted. Made a purchase, signed up for something, downloaded a resource, replied to your email, whatever your goal was.This is the metric that matters to your business, but it's also the hardest to track because it requires connecting email clicks to actions taken elsewhere.Healthy benchmarks:These vary so wildly by industry, email type, and goal that generic benchmarks are useless. Track your own baseline.What trends mean:Low conversion despite high CTR means your landing page or offer is the problem, not your email. People are interested enough to click but something on the other side isn't working.Low conversion with low CTR means the email itself isn't compelling enough to get people to take the first step.What to do:Make sure you're actually tracking conversions. Use UTM parameters, conversion pixels, or unique tracking links so you can attribute actions back to specific emails.If clicks are high but conversions are low, fix what happens after the click. Test your landing page, simplify the conversion path, or adjust your offer.If both clicks and conversions are low, the problem is in the email. Test different subject lines, content formats, and CTAs.Time-to-Open and Time-to-Click PatternsMost people don't think about timing, but when people open and click tells you a lot.If 80% of your opens happen in the first hour after sending, your subject line is strong and your audience is engaged. If opens trickle in over days, you're hitting inactive users or your content isn't time-sensitive enough to prioritize.Click timing is even more interesting. Fast clicks (within minutes of opening) suggest impulse actions or high-intent content. Delayed clicks might mean people are reading carefully or coming back to something they saved.What to do:Look at when your emails get the most engagement and send during those windows. If your audience opens emails at 8am on Tuesdays, don't send at 3pm on Fridays.For transactional emails, fast open times are critical. If it takes hours for someone to see their password reset, that's a problem. Check if your sending is delayed or if emails are getting filtered.Track how timing correlates with conversions. Sometimes the people who click immediately convert poorly (impulse, not ready), while delayed clicks convert better (thoughtful consideration). This changes how you optimize.Re-Engagement PatternsThis isn't a single metric but a pattern to watch: how often do the same people engage with your emails over time?Some subscribers open everything you send. Others open once every few months. Some clicked five emails in a row, then nothing for weeks. These patterns tell you who's genuinely engaged versus who's passively on your list.What to track:Segment your list by engagement recency. Who opened in the last 7 days? 30 days? 90 days? Never?Watch for engagement decay. If someone goes from opening every email to opening every third email to not opening at all, they're slowly churning. Catch them before they're completely disengaged.What to do:Create win-back campaigns for people who haven't engaged in 60-90 days. Ask if they still want to hear from you, offer to change email frequency, or give them a compelling reason to re-engage.For your most engaged subscribers, consider sending them more content or exclusive offers. These are your best customers, don't ignore them by treating everyone the same.Regularly clean your list by removing people who haven't engaged in 6+ months. They're hurting your metrics and costing you money with no benefit.How to Read Metrics TogetherIndividual metrics are useful, but reading them in combination tells you what's actually happening.High opens, low clicks: Subject line works but content doesn't deliver. Your emails promise one thing and deliver another, or your CTAs are weak.Low opens, high clicks: Subject lines are terrible but content is great. The people who do open are highly engaged. Improve your subject lines.High clicks, low conversions: Email is working, but your landing page, offer, or next step is broken. Fix what happens after the click.Rising unsubscribes, stable complaints: People are politely leaving instead of marking you spam. Content mismatch, but you're making it easy to opt out. Good.Rising complaints, rising unsubscribes: People are so frustrated they're taking multiple actions to stop hearing from you. Major content problem or you're emailing the wrong people.High bounces, high complaints: List quality disaster. You're sending to bad addresses and the ones that do exist don't want your emails. Stop immediately and clean your list.Declining engagement across all metrics: General relevance decay. Your content is becoming less interesting, you're sending too frequently, or your audience is changing and you're not adapting.Look at your metrics together every week, not just when something goes wrong. Patterns emerge over time that aren't visible in single sends.Vanity Metrics That Don't Actually MatterSome metrics look impressive but tell you nothing useful:Total subscribers: Meaningless without engagement rates. 100,000 subscribers with 1% engagement is worse than 10,000 with 20% engagement. Quality over quantity always.Email sent count: Sending more emails doesn't mean anything if they're not being read or acted on. Don't celebrate volume, celebrate engagement.List growth rate: Growing fast is only good if you're growing with engaged, relevant subscribers. Adding 1,000 people who never open your emails hurts more than it helps.Delivery rate: This just means the email technically arrived at a server somewhere. It doesn't mean it hit the inbox versus the spam folder. Focus on engagement, not technical delivery.Stop tracking these or at least stop making decisions based on them. They make you feel good without indicating real email health.Start With the Metrics That Impact DeliverabilityYou don't need to track everything at once. Start with the metrics that directly impact your sender reputation: complaint rate, bounce rate, and engagement patterns.Get those right and you'll land in inboxes consistently. Then layer in conversion tracking and more sophisticated analysis as you scale.The goal isn't to obsess over numbers. It's to understand what your audience is telling you through their behavior and respond accordingly. Low engagement means your content isn't relevant. High complaints mean you're annoying people. Rising bounces mean your list is degrading.Fix the signals, and the numbers will improve naturally.

Email metrics explained: what each number means, healthy benchmarks, red flags to watch for, and how to turn analytics into better email performance.

How to Read Email Metrics and Actually Improve Email Performance

Your emails are going to spam, and chances are, you know exactly which ones.The welcome email that 30% of users never see. The password reset that arrives 10 minutes late, buried under promotions. The product update that half your customers miss entirely.Here's what's frustrating: it's probably not your email content that's the problem. It's technical mistakes that are completely fixable but easy to miss if you don't know what spam filters are looking for.I run AutoSend, an email service provider, and I see these mistakes constantly. A founder will email me confused about why their deliverability tanked overnight. I'll look at their setup and immediately spot it: they're using noreply@, or they just sent 10,000 emails from a week-old domain, or they deleted their suppression list and re-uploaded contacts.These aren't edge cases. They're the most common reasons emails land in spam.This guide covers 18 mistakes that destroy email deliverability, organized by severity. Some are critical and will get you blacklisted fast (like bypassing unsubscribes). Others are medium-impact but still hurt your sender reputation over time (like too many links or poor text-to-image ratios).For each mistake, I'll explain what's wrong, why spam filters flag it, and exactly how to fix it. By the end, you'll have a checklist to audit your own email setup and stop losing emails to the spam folder.Let's start with the critical ones.<h3>Missing Email Authentication (SPF, DKIM, DMARC) </h3>Inbox providers automatically flag unauthenticated emails as potential impersonation attempts. Without these three protocols configured, your emails have no way to prove they're legitimately from you. Set them up in your DNS records and verify they're working with authentication checkers.<h3>Using noreply@ or no-reply@ Addresses</h3>These addresses signal to spam filters that you don't want engagement, which is exactly what spam does. ESPs prioritize emails that encourage two-way communication. Use real addresses like hello@, support@, or team@ instead.You can use these emails for transactional email once your sending domain reputation is built. This typically takes 6 to 8 months. But I will recommend after 12 months.<h3>Deleting Contacts and Re-uploading to Bypass Unsubscribes</h3>This violates CAN-SPAM and GDPR laws, and users will hit the spam button when they get emails they already unsubscribed from. Your sender reputation tanks instantly. Suppression lists exist for a reason - respect them permanently. If you want to re-engage people, use proper win-back campaigns for legitimately disengaged users.<h3>Missing Unsubscribe Link and Postal Address in Footer</h3>CAN-SPAM requires both a working unsubscribe mechanism and a physical postal address in every commercial email. Without these, you're breaking the law and giving users no choice but to report you as spam. Every email needs a clear, one-click unsubscribe option and your business address in the footer.<h2>High-Impact Mistakes:</h2>The next group of mistakes won't get you blacklisted overnight, but they'll steadily destroy your sender reputation. These are especially common with new domains or aggressive growth strategies. If you're seeing gradual deliverability decline or struggling to scale your email volume, you're probably making one of these:<h3>Sending Bulk Emails with Brand New Domain</h3>A brand new domain has zero sender reputation. When you immediately blast thousands of emails from it, you look exactly like a spam operation. Warm up your domain over 2-4 weeks, starting with 50-100 emails per day to engaged contacts, then gradually increase volume.<h3>Cold Emailing with New Domain</h3>Combine an unknown sender with unsolicited emails and you've got a double red flag. Even legitimate cold outreach needs a warmed domain first. Start with engaged contacts for a few weeks, then begin cold outreach slowly with smaller volumes. Do read the <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/blog/new-email-domain-warmup-guide">domain warmup</a> guide.<h3>Using URL Shorteners (bit.ly, tinyurl, etc.)</h3>Spammers use these to hide malicious destinations, so filters treat them as red flags. Use full URLs in your emails, or if you must track clicks, use custom domain short links with proper authentication.You don't have to worry about this if you're tracking clicks in AutoSend because we replace your links with our branded tracking domain.<h3>Purchased or Scraped Email Lists</h3>These lists contain spam traps, inactive addresses, and people who never gave permission. Your reputation gets destroyed immediately. Only email people who explicitly opted in to hear from you.<h3>Using Different Domains for From and Reply-To Addresses</h3>When your From address is @company.com but Reply-To is @differentorg.com, it looks like you're trying to hide something. This is a classic phishing technique. Keep both addresses on the same authenticated domain.<h2>Medium-Impact Mistakes</h2>These mistakes won't tank your reputation immediately, but they add up. Each one increases your spam score incrementally, and when you combine several of them, you start seeing problems. They're also the easiest to fix, most requiring simple content or formatting changes:<h3>Overly Designed Emails (Poor Text-to-Image Ratio)</h3>Emails that are mostly images with little text look like advertisements and give spam filters nothing to analyze. Keep a 60/40 or 70/30 text-to-image ratio and always include a plain text version.<h3>Too Many Links in One Email</h3>Each link increases your spam score, and 10+ links screams spam. Keep it to 3-5 links maximum and make each one count.<h3>Ignoring Bounces and Complaints</h3>Continuing to send to addresses that hard bounce or users who complained destroys your sender reputation. Automatically suppress hard bounces and monitor complaint rates closely.<h3>Generic or Spammy Subject Lines</h3>Subject lines with "URGENT!!!", "FREE $$$", "Re: [nothing]" trigger spam filters instantly and look untrustworthy. Write clear, honest subject lines that accurately describe the email content.<h3>Creating False Urgency in Email Copy</h3>Phrases like "ACT NOW!", "Limited time only!", "Expires in 24 hours!" are spam filter triggers and erode trust. Even if you have a legitimate deadline, present it factually without manufactured pressure. Real urgency doesn't need ALL CAPS and multiple exclamation marks.<h3>Not Personalizing Emails (Using "Dear Friend" or "Hey There")</h3>Generic greetings like "Hello dear" or "Hey friend" tell the recipient you don't actually know them, which is exactly what spam does. Use their actual name if you have it. If you're sending to people whose names you don't have, you probably shouldn't be emailing them at all.<h3>Excessive Capitalization and Exclamation Marks!!! </h3>WRITING IN ALL CAPS or using multiple exclamation marks!!! makes you look unprofessional and triggers spam filters. Write like a normal person having a conversation, not someone shouting from an infomercial.<hr><h2>Closing note</h2>You don't need to fix all 18 mistakes at once. Start with the critical ones, especially email authentication and anything involving legal compliance. Those will give you the biggest deliverability improvement immediately.Then work through the high-impact mistakes, particularly if you're using a new domain or seeing inconsistent inbox placement. The medium-impact fixes can come last, but don't ignore them since they compound over time.The good news: most of these are one-time fixes. Set up authentication correctly once, use real email addresses, respect suppression lists, and you've eliminated half the list. The rest are about content and sending patterns, which get easier once you know what to avoid.Fix these mistakes, and your emails will start landing in inboxes instead of spam folders.

Your emails are going to spam, and chances are, you know exactly which ones.The welcome email that 30% of users never see. The password reset that arrives 10 minutes late, buried under promotions. The product update that half your customers miss entirely.Here's what's frustrating: it's probably not your email content that's the problem. It's technical mistakes that are completely fixable but easy to miss if you don't know what spam filters are looking for.I run AutoSend, an email service provider, and I see these mistakes constantly. A founder will email me confused about why their deliverability tanked overnight. I'll look at their setup and immediately spot it: they're using noreply@, or they just sent 10,000 emails from a week-old domain, or they deleted their suppression list and re-uploaded contacts.These aren't edge cases. They're the most common reasons emails land in spam.This guide covers 18 mistakes that destroy email deliverability, organized by severity. Some are critical and will get you blacklisted fast (like bypassing unsubscribes). Others are medium-impact but still hurt your sender reputation over time (like too many links or poor text-to-image ratios).For each mistake, I'll explain what's wrong, why spam filters flag it, and exactly how to fix it. By the end, you'll have a checklist to audit your own email setup and stop losing emails to the spam folder.Let's start with the critical ones.Missing Email Authentication (SPF, DKIM, DMARC) Inbox providers automatically flag unauthenticated emails as potential impersonation attempts. Without these three protocols configured, your emails have no way to prove they're legitimately from you. Set them up in your DNS records and verify they're working with authentication checkers.Using noreply@ or no-reply@ AddressesThese addresses signal to spam filters that you don't want engagement, which is exactly what spam does. ESPs prioritize emails that encourage two-way communication. Use real addresses like hello@, support@, or team@ instead.You can use these emails for transactional email once your sending domain reputation is built. This typically takes 6 to 8 months. But I will recommend after 12 months.Deleting Contacts and Re-uploading to Bypass UnsubscribesThis violates CAN-SPAM and GDPR laws, and users will hit the spam button when they get emails they already unsubscribed from. Your sender reputation tanks instantly. Suppression lists exist for a reason - respect them permanently. If you want to re-engage people, use proper win-back campaigns for legitimately disengaged users.Missing Unsubscribe Link and Postal Address in FooterCAN-SPAM requires both a working unsubscribe mechanism and a physical postal address in every commercial email. Without these, you're breaking the law and giving users no choice but to report you as spam. Every email needs a clear, one-click unsubscribe option and your business address in the footer.High-Impact Mistakes:The next group of mistakes won't get you blacklisted overnight, but they'll steadily destroy your sender reputation. These are especially common with new domains or aggressive growth strategies. If you're seeing gradual deliverability decline or struggling to scale your email volume, you're probably making one of these:Sending Bulk Emails with Brand New DomainA brand new domain has zero sender reputation. When you immediately blast thousands of emails from it, you look exactly like a spam operation. Warm up your domain over 2-4 weeks, starting with 50-100 emails per day to engaged contacts, then gradually increase volume.Cold Emailing with New DomainCombine an unknown sender with unsolicited emails and you've got a double red flag. Even legitimate cold outreach needs a warmed domain first. Start with engaged contacts for a few weeks, then begin cold outreach slowly with smaller volumes. Do read the domain warmup guide.Using URL Shorteners (bit.ly, tinyurl, etc.)Spammers use these to hide malicious destinations, so filters treat them as red flags. Use full URLs in your emails, or if you must track clicks, use custom domain short links with proper authentication.You don't have to worry about this if you're tracking clicks in AutoSend because we replace your links with our branded tracking domain.Purchased or Scraped Email ListsThese lists contain spam traps, inactive addresses, and people who never gave permission. Your reputation gets destroyed immediately. Only email people who explicitly opted in to hear from you.Using Different Domains for From and Reply-To AddressesWhen your From address is @company.com but Reply-To is @differentorg.com, it looks like you're trying to hide something. This is a classic phishing technique. Keep both addresses on the same authenticated domain.Medium-Impact MistakesThese mistakes won't tank your reputation immediately, but they add up. Each one increases your spam score incrementally, and when you combine several of them, you start seeing problems. They're also the easiest to fix, most requiring simple content or formatting changes:Overly Designed Emails (Poor Text-to-Image Ratio)Emails that are mostly images with little text look like advertisements and give spam filters nothing to analyze. Keep a 60/40 or 70/30 text-to-image ratio and always include a plain text version.Too Many Links in One EmailEach link increases your spam score, and 10+ links screams spam. Keep it to 3-5 links maximum and make each one count.Ignoring Bounces and ComplaintsContinuing to send to addresses that hard bounce or users who complained destroys your sender reputation. Automatically suppress hard bounces and monitor complaint rates closely.Generic or Spammy Subject LinesSubject lines with "URGENT!!!", "FREE $$$", "Re: [nothing]" trigger spam filters instantly and look untrustworthy. Write clear, honest subject lines that accurately describe the email content.Creating False Urgency in Email CopyPhrases like "ACT NOW!", "Limited time only!", "Expires in 24 hours!" are spam filter triggers and erode trust. Even if you have a legitimate deadline, present it factually without manufactured pressure. Real urgency doesn't need ALL CAPS and multiple exclamation marks.Not Personalizing Emails (Using "Dear Friend" or "Hey There")Generic greetings like "Hello dear" or "Hey friend" tell the recipient you don't actually know them, which is exactly what spam does. Use their actual name if you have it. If you're sending to people whose names you don't have, you probably shouldn't be emailing them at all.Excessive Capitalization and Exclamation Marks!!! WRITING IN ALL CAPS or using multiple exclamation marks!!! makes you look unprofessional and triggers spam filters. Write like a normal person having a conversation, not someone shouting from an infomercial.Closing noteYou don't need to fix all 18 mistakes at once. Start with the critical ones, especially email authentication and anything involving legal compliance. Those will give you the biggest deliverability improvement immediately.Then work through the high-impact mistakes, particularly if you're using a new domain or seeing inconsistent inbox placement. The medium-impact fixes can come last, but don't ignore them since they compound over time.The good news: most of these are one-time fixes. Set up authentication correctly once, use real email addresses, respect suppression lists, and you've eliminated half the list. The rest are about content and sending patterns, which get easier once you know what to avoid.Fix these mistakes, and your emails will start landing in inboxes instead of spam folders.

18 email mistakes killing your deliverability: missing authentication, new domain blasts, URL shorteners, poor personalization, and more. Plus how to fix each.

How to Stop Emails from Going to Spam (Complete Guide)

Starting to send emails from a brand new domain without proper preparation will land your messages in spam folders. Email providers like Gmail, Outlook, and Yahoo don't trust new domains by default. They have no history with you, no data on whether you're a legitimate sender or a spammer.This is where domain warming comes in. It's the process of gradually building your sender reputation by slowly increasing your email volume over 4-8 weeks while maintaining strong engagement metrics. Skip this step, and you'll spend months fighting deliverability problems. Do it properly, and you'll establish a foundation for consistently high inbox placement.This guide covers everything you need to know about warming up a new domain for both transactional and marketing emails.<h2>Why Domain Warming Matters</h2>Email providers like Gmail, Outlook, and Yahoo don't trust new domains by default. They have no history with you. No data on whether your emails are legitimate or spam. So they watch closely.When you suddenly start sending thousands of emails from a fresh domain, it triggers red flags. The algorithm thinks: "This looks like a spammer who just registered a domain." Your emails get filtered, your domain gets a poor reputation score, and you're starting from a much worse position than if you'd warmed up properly.The warming process proves you're legitimate. You're gradually increasing volume, maintaining good engagement, and following email best practices. This builds sender reputation and trains inbox providers to trust your domain.<h2>Before You Start: Technical Foundation</h2>Domain warming isn't just about volume. You need the technical infrastructure in place first.Set up your DNS authentication records properly. This means SPF, DKIM, and DMARC. These records verify that you're authorized to send emails from your domain and help prevent spoofing. Without them, you'll struggle to reach inboxes regardless of how slowly you ramp up. If you need help with the technical setup, check out <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/blog/how-spf-dkim-and-dmarc-work">how SPF, DKIM, and DMARC works</a>.If you're using AutoSend, <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://docs.autosend.com/domain">here's how to setup DNS records.</a>Use a dedicated subdomain for email. Avoid sending from your main domain like <code>example.com</code>. Use a subdomain like <code>mail.example.com</code> or <code>send.example.com</code>. This protects your main domain's reputation if something goes wrong with your email sending. It also gives you better control over authentication and monitoring.Set up proper reverse DNS (rDNS). Your IP address should have a PTR record that points back to your sending domain. Most email service providers including AutoSend handle this automatically, but verify it's configured correctly.Create a real postmaster and abuse email address. Set up <code>postmaster@yourdomain.com</code> and <code>abuse@yourdomain.com</code> that actually receive mail. Inbox providers check these addresses and may send important feedback to them.Configure your email infrastructure. Whether you're using AutoSend or another provider, make sure your <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/transactional-emails">email API</a> integration is working, you can track bounces and complaints, and your webhook endpoints are ready to receive delivery events.<h2>Understanding the Warming Timeline</h2>The warming process typically takes 4-8 weeks depending on your sending volume. Here's why it takes this long:Inbox providers are watching multiple signals over time. They look at your sending patterns, engagement rates, spam complaints, bounce rates, and consistency. They need enough data to establish that you're a legitimate sender. Rushing this process by jumping to high volume too quickly will hurt your reputation.Different volume levels require different approaches. Sending 1,000 emails per day requires a different strategy than sending 100,000 per day.<h2>The Week-by-Week Warming Schedule</h2>For Low Volume Senders (up to 5,000 emails/day)<ol><li>Week 1: Start with 50-100 emails per day. Send to your most engaged contacts. These should be people who definitely want your emails and are likely to open them.</li><li>Week 2: Increase to 200-500 emails per day. Maintain high engagement by sending relevant content.</li><li>Week 3: Move to 1,000-2,000 emails per day. You can start including slightly less engaged contacts, but still focus on quality over quantity.</li><li>Week 4: Reach 3,000-5,000 emails per day. By now, you should see consistent deliverability and can operate at your target volume.</li></ol>For Medium Volume Senders (5,000-50,000 emails/day)<ol><li>Week 1: Send 200-500 emails per day to your most engaged segments.</li><li>Week 2: Increase to 1,000-2,000 emails per day.</li><li>Week 3: Jump to 5,000-10,000 emails per day.</li><li>Week 4: Reach 15,000-20,000 emails per day.</li><li>Week 5: Scale to 30,000-40,000 emails per day.</li><li>Week 6: Hit your target volume of 50,000 emails per day.</li></ol>For High Volume Senders (50,000+ emails/day)<ol><li>Week 1-2: Start with 500-1,000 emails per day, focusing exclusively on highly engaged contacts.</li><li>Week 3-4: Increase to 10,000-20,000 emails per day.</li><li>Week 5-6: Scale to 40,000-80,000 emails per day.</li><li>Week 7-8: Reach 100,000+ emails per day and maintain consistent patterns.</li></ol>For high volume sending, you may want to split across multiple dedicated IPs and warm each IP separately following a similar schedule.<h2>The Most Important Rule: Consistency</h2>Don't send 1,000 emails on Monday, skip Tuesday, send 5,000 on Wednesday, and nothing on Thursday. Inconsistent sending patterns look suspicious to inbox providers.Send every day or every business day during your warming period. Maintain a regular schedule. If you're warming up for a newsletter that goes out weekly, send smaller test batches to engaged contacts on your off days to maintain consistency.Keep your daily volume increases gradual. Don't double your volume overnight. A 30-50% increase every few days is much safer than aggressive jumps.<h2>Engagement is Your Best Friend</h2>Inbox providers measure engagement heavily. Opens, clicks, replies, and forwards signal that people want your emails. Spam complaints, deletes without opening, and ignoring your emails signal the opposite.Start with your most engaged contacts. These are people who have recently interacted with you, explicitly opted in, or have a history of engagement. For transactional emails, this means customers who just completed an action. For marketing, this means subscribers who recently joined your list or have opened recent emails.Send content people actually want. During warming, every email matters. Don't send mediocre content just to hit your daily volume. Send your best stuff. If you're warming a transactional domain, trigger real, valuable notifications. If you're warming a marketing domain, send genuinely useful content to subscribers who will appreciate it.Avoid sending to old, cold lists during warming. That list of 50,000 contacts you collected over three years? Don't send to them during warming. Many of those email addresses are probably dead, the engaged people have moved on, and you'll see terrible metrics. Save cold reactivation campaigns for after you've established your reputation.Make it easy to engage. Use clear, compelling subject lines. Make your emails mobile-friendly. Include a clear call-to-action. The easier you make it for people to engage positively, the better your reputation will be.<h2>Segmentation Strategy During Warming</h2>For marketing email warming, segment your list by engagement level. Create tiers:Tier 1 - Highly Engaged: Opened or clicked in the last 30 days, recent subscribers, customers who regularly interact with you.Tier 2 - Moderately Engaged: Opened in the last 90 days, less frequent but consistent engagement.Tier 3 - Low Engagement: Opened in the last 180 days, infrequent interaction.Tier 4 - Cold/Unengaged: No opens in 180+ days, very old subscribers.During warming, follow this sequence:<ul><li>Weeks 1-2: Only Tier 1</li><li>Weeks 3-4: Tier 1 + Tier 2</li><li>Weeks 5-6: Tier 1 + Tier 2 + Tier 3</li><li>Week 7+: All tiers, but consider a reactivation campaign for Tier 4</li></ul><h2>Transactional vs. Marketing Email Warming</h2>The principles are the same, but the execution differs.<a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/blog/how-to-warm-up-a-new-domain-for-transactional-emails">Transactional email warming</a> is often easier because engagement rates are naturally higher. People want their receipts, notifications, and account updates. Your strategy should focus on:<ul><li>Starting with the most critical, time-sensitive notifications first. Password resets and order confirmations have the highest engagement. Gradually add less critical notifications like weekly digests or feature announcements.</li><li>Maintaining consistent daily volume by staggering non-urgent notifications if needed. If you don't have enough natural transactional volume during warming, you can supplement with well-targeted marketing content to engaged users.</li><li>Avoiding bulk promotional sends during the warming period. Save marketing campaigns for after you've established transactional credibility.</li></ul>Marketing email warming requires more careful planning because engagement rates vary more. Your strategy should emphasize:<ul><li>Building a warming calendar with your best content scheduled for the warming period. Don't waste your warming sends on weak campaigns.</li><li>Segmenting aggressively by engagement level as described above. Never send to your full list during warming.</li><li>Adjusting your normal send schedule if needed. If you usually send twice a week, continue that schedule but only to your most engaged segments initially.</li></ul>Creating special content that encourages engagement during warming. Ask questions, run polls, share genuinely valuable resources. This isn't the time for hard sells.<h2>Monitoring Your Progress</h2>Track these metrics daily during warming:Delivery rate: Should stay above 95%. If it drops, you have list quality issues or technical problems.Bounce rate: Should be under 3%, ideally under 1%. High bounces damage your reputation quickly. Remove bounced addresses immediately and investigate why you're seeing bounces.Spam complaint rate: Must stay under 0.1% (1 complaint per 1,000 emails). Anything higher is a serious problem. If you're seeing high complaints, stop sending, identify the issue, and fix it before continuing.Open rate: This varies by industry, but you want to see consistent or improving open rates as you warm up. If open rates drop as you increase volume, you're scaling too fast or including less engaged contacts too early.Click rate: Similar to open rate. Stable or improving click rates indicate healthy engagement.Spam folder placement: Use seed testing tools to check where your emails land across different providers. If you're hitting spam folders frequently, slow down your warming and improve engagement.Most email service providers give you access to these metrics in real-time. <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline underline underline underline-offset-2 decoration-1 decoration-current/40 hover:decoration-current focus:decoration-current" href="https://autosend.io">AutoSend</a> shows all of this in your dashboard, including detailed activity tracking and webhook events for bounces and complaints.<h2>Tools for Testing and Monitoring</h2><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline underline underline underline-offset-2 decoration-1 decoration-current/40 hover:decoration-current focus:decoration-current" href="https://www.mail-tester.com/">Mail-Tester</a>: Quick check of your email's spam score and technical setup. Useful for spot-checking during warming.<a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline underline underline underline-offset-2 decoration-1 decoration-current/40 hover:decoration-current focus:decoration-current" href="https://glockapps.com/">GlockApps</a>: Send test emails to seed lists across major providers and see exactly where you land. Use this weekly during warming to catch deliverability issues early.<a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline underline underline underline-offset-2 decoration-1 decoration-current/40 hover:decoration-current focus:decoration-current" href="https://postmaster.google.com/">Google Postmaster Tools</a>: If you're sending significant volume to Gmail addresses, set up Postmaster Tools. It shows your domain reputation, spam rate, and feedback loop data directly from Google.<a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline underline underline underline-offset-2 decoration-1 decoration-current/40 hover:decoration-current focus:decoration-current" href="https://sendersupport.olc.protection.outlook.com/snds/">Microsoft SNDS</a>: Similar to Google Postmaster but for Outlook/Hotmail. Monitor your IP reputation and complaint rates.Your email provider's analytics: Whatever platform you're using should give you detailed metrics. Check them daily during warming and watch for trends.<h2>Common Mistakes to Avoid</h2>Don't buy or scrape email lists. This kills your reputation instantly. Only send to people who explicitly opted in to receive your emails.Don't send from free email provider addresses (Gmail, Yahoo, etc.) for bulk sending. Use your own domain with proper authentication.Don't ignore bounces and complaints. These are direct signals that something is wrong. Address them immediately.Don't use misleading subject lines or hide your identity. This generates complaints and damages trust.Don't forget to include a working unsubscribe link. It's required by law and helps maintain a healthy list. People who unsubscribe are better than people who mark you as spam.Don't panic if you see occasional spam folder placement during warming. Some variation is normal. Look for trends, not individual incidents.<h2>Special Scenarios</h2>Warming multiple domains: If you need to send from multiple domains, warm each separately. Don't try to transfer reputation from one domain to another. You can run warming processes in parallel if needed.Adding a new IP address: If you're adding a new dedicated IP to an already-warmed domain, you still need to warm the IP. Use a similar schedule but you can move slightly faster since your domain already has reputation.Switching email providers: Your domain reputation follows your domain, not your provider. However, you may need a brief re-warming period (1-2 weeks) when switching providers, especially if moving to dedicated IPs.Seasonal senders: If you only send emails seasonally, plan extra time for warming when you start each season. Your reputation degrades over time without sending activity.<h2>After Warming: Maintaining Your Reputation</h2>Once you've completed your warming schedule and reached your target volume, the work isn't over. Sender reputation requires ongoing maintenance.Keep sending consistently. Large gaps in sending or dramatic volume changes can hurt your reputation even after warming.Continue monitoring your metrics. If you see bounce rates creeping up or engagement dropping, investigate immediately.Clean your list regularly. Remove bounces immediately, suppress complaints, and consider removing addresses that haven't engaged in 6-12 months.Segment your sends to maintain good engagement. Don't send everything to everyone just because you can.Test new content approaches gradually. If you want to try a new format or messaging strategy, test with your most engaged segments first.<h2>Starting Your Warming Process</h2>Domain warming requires patience, but it's worth the investment. A properly warmed domain with strong reputation delivers better results for years. Rushing the process saves you a few weeks now but costs you months of poor deliverability later.Start with your technical foundation. Make sure your DNS authentication is correct and your infrastructure is ready. Then begin sending small volumes to your most engaged contacts and gradually scale up following the schedules outlined above.Monitor your metrics daily. Stay consistent with your sending. Focus on engagement over volume. And give yourself the full 4-8 weeks to establish your reputation properly.The domains that skip warming are the ones dealing with spam folder problems six months later. The domains that warm properly are the ones hitting inboxes consistently and driving real results from their email programs.

Starting to send emails from a brand new domain without proper preparation will land your messages in spam folders. Email providers like Gmail, Outlook, and Yahoo don't trust new domains by default. They have no history with you, no data on whether you're a legitimate sender or a spammer.This is where domain warming comes in. It's the process of gradually building your sender reputation by slowly increasing your email volume over 4-8 weeks while maintaining strong engagement metrics. Skip this step, and you'll spend months fighting deliverability problems. Do it properly, and you'll establish a foundation for consistently high inbox placement.This guide covers everything you need to know about warming up a new domain for both transactional and marketing emails.Why Domain Warming MattersEmail providers like Gmail, Outlook, and Yahoo don't trust new domains by default. They have no history with you. No data on whether your emails are legitimate or spam. So they watch closely.When you suddenly start sending thousands of emails from a fresh domain, it triggers red flags. The algorithm thinks: "This looks like a spammer who just registered a domain." Your emails get filtered, your domain gets a poor reputation score, and you're starting from a much worse position than if you'd warmed up properly.The warming process proves you're legitimate. You're gradually increasing volume, maintaining good engagement, and following email best practices. This builds sender reputation and trains inbox providers to trust your domain.Before You Start: Technical FoundationDomain warming isn't just about volume. You need the technical infrastructure in place first.Set up your DNS authentication records properly. This means SPF, DKIM, and DMARC. These records verify that you're authorized to send emails from your domain and help prevent spoofing. Without them, you'll struggle to reach inboxes regardless of how slowly you ramp up. If you need help with the technical setup, check out how SPF, DKIM, and DMARC works.If you're using AutoSend, here's how to setup DNS records.Use a dedicated subdomain for email. Avoid sending from your main domain like example.com. Use a subdomain like mail.example.com or send.example.com. This protects your main domain's reputation if something goes wrong with your email sending. It also gives you better control over authentication and monitoring.Set up proper reverse DNS (rDNS). Your IP address should have a PTR record that points back to your sending domain. Most email service providers including AutoSend handle this automatically, but verify it's configured correctly.Create a real postmaster and abuse email address. Set up postmaster@yourdomain.com and abuse@yourdomain.com that actually receive mail. Inbox providers check these addresses and may send important feedback to them.Configure your email infrastructure. Whether you're using AutoSend or another provider, make sure your email API integration is working, you can track bounces and complaints, and your webhook endpoints are ready to receive delivery events.Understanding the Warming TimelineThe warming process typically takes 4-8 weeks depending on your sending volume. Here's why it takes this long:Inbox providers are watching multiple signals over time. They look at your sending patterns, engagement rates, spam complaints, bounce rates, and consistency. They need enough data to establish that you're a legitimate sender. Rushing this process by jumping to high volume too quickly will hurt your reputation.Different volume levels require different approaches. Sending 1,000 emails per day requires a different strategy than sending 100,000 per day.The Week-by-Week Warming ScheduleFor Low Volume Senders (up to 5,000 emails/day)Week 1: Start with 50-100 emails per day. Send to your most engaged contacts. These should be people who definitely want your emails and are likely to open them.Week 2: Increase to 200-500 emails per day. Maintain high engagement by sending relevant content.Week 3: Move to 1,000-2,000 emails per day. You can start including slightly less engaged contacts, but still focus on quality over quantity.Week 4: Reach 3,000-5,000 emails per day. By now, you should see consistent deliverability and can operate at your target volume.For Medium Volume Senders (5,000-50,000 emails/day)Week 1: Send 200-500 emails per day to your most engaged segments.Week 2: Increase to 1,000-2,000 emails per day.Week 3: Jump to 5,000-10,000 emails per day.Week 4: Reach 15,000-20,000 emails per day.Week 5: Scale to 30,000-40,000 emails per day.Week 6: Hit your target volume of 50,000 emails per day.For High Volume Senders (50,000+ emails/day)Week 1-2: Start with 500-1,000 emails per day, focusing exclusively on highly engaged contacts.Week 3-4: Increase to 10,000-20,000 emails per day.Week 5-6: Scale to 40,000-80,000 emails per day.Week 7-8: Reach 100,000+ emails per day and maintain consistent patterns.For high volume sending, you may want to split across multiple dedicated IPs and warm each IP separately following a similar schedule.The Most Important Rule: ConsistencyDon't send 1,000 emails on Monday, skip Tuesday, send 5,000 on Wednesday, and nothing on Thursday. Inconsistent sending patterns look suspicious to inbox providers.Send every day or every business day during your warming period. Maintain a regular schedule. If you're warming up for a newsletter that goes out weekly, send smaller test batches to engaged contacts on your off days to maintain consistency.Keep your daily volume increases gradual. Don't double your volume overnight. A 30-50% increase every few days is much safer than aggressive jumps.Engagement is Your Best FriendInbox providers measure engagement heavily. Opens, clicks, replies, and forwards signal that people want your emails. Spam complaints, deletes without opening, and ignoring your emails signal the opposite.Start with your most engaged contacts. These are people who have recently interacted with you, explicitly opted in, or have a history of engagement. For transactional emails, this means customers who just completed an action. For marketing, this means subscribers who recently joined your list or have opened recent emails.Send content people actually want. During warming, every email matters. Don't send mediocre content just to hit your daily volume. Send your best stuff. If you're warming a transactional domain, trigger real, valuable notifications. If you're warming a marketing domain, send genuinely useful content to subscribers who will appreciate it.Avoid sending to old, cold lists during warming. That list of 50,000 contacts you collected over three years? Don't send to them during warming. Many of those email addresses are probably dead, the engaged people have moved on, and you'll see terrible metrics. Save cold reactivation campaigns for after you've established your reputation.Make it easy to engage. Use clear, compelling subject lines. Make your emails mobile-friendly. Include a clear call-to-action. The easier you make it for people to engage positively, the better your reputation will be.Segmentation Strategy During WarmingFor marketing email warming, segment your list by engagement level. Create tiers:Tier 1 - Highly Engaged: Opened or clicked in the last 30 days, recent subscribers, customers who regularly interact with you.Tier 2 - Moderately Engaged: Opened in the last 90 days, less frequent but consistent engagement.Tier 3 - Low Engagement: Opened in the last 180 days, infrequent interaction.Tier 4 - Cold/Unengaged: No opens in 180+ days, very old subscribers.During warming, follow this sequence:Weeks 1-2: Only Tier 1Weeks 3-4: Tier 1 + Tier 2Weeks 5-6: Tier 1 + Tier 2 + Tier 3Week 7+: All tiers, but consider a reactivation campaign for Tier 4Transactional vs. Marketing Email WarmingThe principles are the same, but the execution differs.Transactional email warming is often easier because engagement rates are naturally higher. People want their receipts, notifications, and account updates. Your strategy should focus on:Starting with the most critical, time-sensitive notifications first. Password resets and order confirmations have the highest engagement. Gradually add less critical notifications like weekly digests or feature announcements.Maintaining consistent daily volume by staggering non-urgent notifications if needed. If you don't have enough natural transactional volume during warming, you can supplement with well-targeted marketing content to engaged users.Avoiding bulk promotional sends during the warming period. Save marketing campaigns for after you've established transactional credibility.Marketing email warming requires more careful planning because engagement rates vary more. Your strategy should emphasize:Building a warming calendar with your best content scheduled for the warming period. Don't waste your warming sends on weak campaigns.Segmenting aggressively by engagement level as described above. Never send to your full list during warming.Adjusting your normal send schedule if needed. If you usually send twice a week, continue that schedule but only to your most engaged segments initially.Creating special content that encourages engagement during warming. Ask questions, run polls, share genuinely valuable resources. This isn't the time for hard sells.Monitoring Your ProgressTrack these metrics daily during warming:Delivery rate: Should stay above 95%. If it drops, you have list quality issues or technical problems.Bounce rate: Should be under 3%, ideally under 1%. High bounces damage your reputation quickly. Remove bounced addresses immediately and investigate why you're seeing bounces.Spam complaint rate: Must stay under 0.1% (1 complaint per 1,000 emails). Anything higher is a serious problem. If you're seeing high complaints, stop sending, identify the issue, and fix it before continuing.Open rate: This varies by industry, but you want to see consistent or improving open rates as you warm up. If open rates drop as you increase volume, you're scaling too fast or including less engaged contacts too early.Click rate: Similar to open rate. Stable or improving click rates indicate healthy engagement.Spam folder placement: Use seed testing tools to check where your emails land across different providers. If you're hitting spam folders frequently, slow down your warming and improve engagement.Most email service providers give you access to these metrics in real-time. AutoSend shows all of this in your dashboard, including detailed activity tracking and webhook events for bounces and complaints.Tools for Testing and MonitoringMail-Tester: Quick check of your email's spam score and technical setup. Useful for spot-checking during warming.GlockApps: Send test emails to seed lists across major providers and see exactly where you land. Use this weekly during warming to catch deliverability issues early.Google Postmaster Tools: If you're sending significant volume to Gmail addresses, set up Postmaster Tools. It shows your domain reputation, spam rate, and feedback loop data directly from Google.Microsoft SNDS: Similar to Google Postmaster but for Outlook/Hotmail. Monitor your IP reputation and complaint rates.Your email provider's analytics: Whatever platform you're using should give you detailed metrics. Check them daily during warming and watch for trends.Common Mistakes to AvoidDon't buy or scrape email lists. This kills your reputation instantly. Only send to people who explicitly opted in to receive your emails.Don't send from free email provider addresses (Gmail, Yahoo, etc.) for bulk sending. Use your own domain with proper authentication.Don't ignore bounces and complaints. These are direct signals that something is wrong. Address them immediately.Don't use misleading subject lines or hide your identity. This generates complaints and damages trust.Don't forget to include a working unsubscribe link. It's required by law and helps maintain a healthy list. People who unsubscribe are better than people who mark you as spam.Don't panic if you see occasional spam folder placement during warming. Some variation is normal. Look for trends, not individual incidents.Special ScenariosWarming multiple domains: If you need to send from multiple domains, warm each separately. Don't try to transfer reputation from one domain to another. You can run warming processes in parallel if needed.Adding a new IP address: If you're adding a new dedicated IP to an already-warmed domain, you still need to warm the IP. Use a similar schedule but you can move slightly faster since your domain already has reputation.Switching email providers: Your domain reputation follows your domain, not your provider. However, you may need a brief re-warming period (1-2 weeks) when switching providers, especially if moving to dedicated IPs.Seasonal senders: If you only send emails seasonally, plan extra time for warming when you start each season. Your reputation degrades over time without sending activity.After Warming: Maintaining Your ReputationOnce you've completed your warming schedule and reached your target volume, the work isn't over. Sender reputation requires ongoing maintenance.Keep sending consistently. Large gaps in sending or dramatic volume changes can hurt your reputation even after warming.Continue monitoring your metrics. If you see bounce rates creeping up or engagement dropping, investigate immediately.Clean your list regularly. Remove bounces immediately, suppress complaints, and consider removing addresses that haven't engaged in 6-12 months.Segment your sends to maintain good engagement. Don't send everything to everyone just because you can.Test new content approaches gradually. If you want to try a new format or messaging strategy, test with your most engaged segments first.Starting Your Warming ProcessDomain warming requires patience, but it's worth the investment. A properly warmed domain with strong reputation delivers better results for years. Rushing the process saves you a few weeks now but costs you months of poor deliverability later.Start with your technical foundation. Make sure your DNS authentication is correct and your infrastructure is ready. Then begin sending small volumes to your most engaged contacts and gradually scale up following the schedules outlined above.Monitor your metrics daily. Stay consistent with your sending. Focus on engagement over volume. And give yourself the full 4-8 weeks to establish your reputation properly.The domains that skip warming are the ones dealing with spam folder problems six months later. The domains that warm properly are the ones hitting inboxes consistently and driving real results from their email programs.

Learn how to warm up a new email domain with proven schedules and strategies. Avoid spam folders and build lasting sender reputation.

How to Warm Up a New Email Domain: Step-by-Step Guide for High Deliverability

<a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com">AutoSend</a> and <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://dodopayments.com/">Dodo Payments</a> have partnered to bring automated transactional email capabilities to the Dodo payment platform. Starting today, Dodo Payments customers can seamlessly integrate AutoSend's email API to handle all payment-related notifications, from transaction confirmations to subscription updates.<h2>Why Transactional Emails Matter for Payment Platforms</h2>When it comes to payments, communication timing is everything. Customers expect immediate confirmation when their payment goes through, prompt notification if something goes wrong, and clear updates about their subscriptions. These aren't nice-to-have emails; they're essential touchpoints that build trust and reduce support inquiries.But building reliable email infrastructure is complex. Between managing deliverability, handling templates, ensuring proper authentication, and scaling to send thousands of emails reliably, most teams would rather focus on their core product. That's exactly what this partnership solves.<h2>How the Integration Works</h2>The AutoSend and Dodo Payments integration works through Dodo's webhook system, automatically triggering emails based on payment events. When a payment succeeds, fails, or when a subscription is created or updated, Dodo Payments can instantly send the appropriate notification through AutoSend's API.Setup takes just a few minutes. Dodo Payments users navigate to their webhook settings, select the AutoSend integration, enter their API key, and configure which events should trigger emails. The integration handles the rest, transforming payment event data into properly formatted email requests.<h2>What You Can Build</h2>The integration supports the full range of payment communications your customers need:<ul><li>Payment confirmations that arrive seconds after a successful transaction, including order details, amounts, and receipt information. These emails set the tone for the entire customer experience and reduce "did my payment go through?" anxiety.</li><li>Subscription welcome emails that greet new subscribers with account details, billing information, and next steps. First impressions matter, and a well-crafted welcome email helps customers feel confident about their purchase.</li><li>Failed payment notifications that alert customers to issues while providing clear next steps. Instead of discovering a failed payment days later, customers get immediate notification with actionable guidance to resolve the issue.</li><li>Refund confirmations that provide transparency and reassurance when transactions are reversed. Clear communication during refunds helps maintain customer relationships even when things don't work out.</li></ul><h2>Key Features Built for Payment Emails</h2>The integration is designed specifically for transactional email needs:<ul><li>Dynamic personalization lets you inject customer names, payment amounts, transaction IDs, subscription details, and any other event data directly into your emails. Every message feels personal and relevant because it includes the exact information customers need.</li><li>Template system allows you to design your emails once in AutoSend, then reference them by ID when sending. Update your email design in one place, and all future sends automatically use the latest version. No code deployments required for design updates.</li><li>Domain verification ensures your emails authenticate properly and land in inboxes, not spam folders. AutoSend's verification process helps you set up SPF, DKIM, and DMARC records correctly, giving your transactional emails the deliverability they deserve.</li><li>Real-time sending means emails go out immediately when payment events occur. No queues, no delays, just instant communication when customers need it most.</li></ul><h3>Technical Simplicity</h3>From a technical perspective, the integration eliminates the need to write custom webhook handlers or email formatting logic. Dodo Payments handles the webhook receipt and event parsing, then transforms the data into AutoSend's API format automatically. Your templates define how the data appears in emails, and AutoSend handles delivery.For developers who want more control, the integration provides full access to AutoSend's API parameters. You can customize sender addresses, reply-to addresses, add CC or BCC recipients, attach files, and include custom headers. The integration is as simple or sophisticated as your use case requires.<h3>Getting Started</h3>Setting up the AutoSend integration takes just a few minutes. Head to your Dodo Payments dashboard, navigate to webhooks, select AutoSend from the integrations list, and enter your API key. If you don't have an AutoSend account yet, you can sign up and get your API key from the dashboard.Full documentation, including code examples and troubleshooting guides, is available at <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://docs.dodopayments.com/integrations/autosend">https://docs.dodopayments.com/integrations/autosend</a><h3>Looking Forward</h3>This partnership represents our commitment to making reliable email infrastructure accessible to every platform that needs it. Dodo Payments customers can now deliver payment communications with the same reliability they bring to payment processing itself.We're here to support you as you roll out the integration. If you have questions or feedback, our team is available through AutoSend's support channels.

AutoSend and Dodo Payments have partnered to bring automated transactional email capabilities to the Dodo payment platform. Starting today, Dodo Payments customers can seamlessly integrate AutoSend's email API to handle all payment-related notifications, from transaction confirmations to subscription updates.Why Transactional Emails Matter for Payment PlatformsWhen it comes to payments, communication timing is everything. Customers expect immediate confirmation when their payment goes through, prompt notification if something goes wrong, and clear updates about their subscriptions. These aren't nice-to-have emails; they're essential touchpoints that build trust and reduce support inquiries.But building reliable email infrastructure is complex. Between managing deliverability, handling templates, ensuring proper authentication, and scaling to send thousands of emails reliably, most teams would rather focus on their core product. That's exactly what this partnership solves.How the Integration WorksThe AutoSend and Dodo Payments integration works through Dodo's webhook system, automatically triggering emails based on payment events. When a payment succeeds, fails, or when a subscription is created or updated, Dodo Payments can instantly send the appropriate notification through AutoSend's API.Setup takes just a few minutes. Dodo Payments users navigate to their webhook settings, select the AutoSend integration, enter their API key, and configure which events should trigger emails. The integration handles the rest, transforming payment event data into properly formatted email requests.What You Can BuildThe integration supports the full range of payment communications your customers need:Payment confirmations that arrive seconds after a successful transaction, including order details, amounts, and receipt information. These emails set the tone for the entire customer experience and reduce "did my payment go through?" anxiety.Subscription welcome emails that greet new subscribers with account details, billing information, and next steps. First impressions matter, and a well-crafted welcome email helps customers feel confident about their purchase.Failed payment notifications that alert customers to issues while providing clear next steps. Instead of discovering a failed payment days later, customers get immediate notification with actionable guidance to resolve the issue.Refund confirmations that provide transparency and reassurance when transactions are reversed. Clear communication during refunds helps maintain customer relationships even when things don't work out.Key Features Built for Payment EmailsThe integration is designed specifically for transactional email needs:Dynamic personalization lets you inject customer names, payment amounts, transaction IDs, subscription details, and any other event data directly into your emails. Every message feels personal and relevant because it includes the exact information customers need.Template system allows you to design your emails once in AutoSend, then reference them by ID when sending. Update your email design in one place, and all future sends automatically use the latest version. No code deployments required for design updates.Domain verification ensures your emails authenticate properly and land in inboxes, not spam folders. AutoSend's verification process helps you set up SPF, DKIM, and DMARC records correctly, giving your transactional emails the deliverability they deserve.Real-time sending means emails go out immediately when payment events occur. No queues, no delays, just instant communication when customers need it most.Technical SimplicityFrom a technical perspective, the integration eliminates the need to write custom webhook handlers or email formatting logic. Dodo Payments handles the webhook receipt and event parsing, then transforms the data into AutoSend's API format automatically. Your templates define how the data appears in emails, and AutoSend handles delivery.For developers who want more control, the integration provides full access to AutoSend's API parameters. You can customize sender addresses, reply-to addresses, add CC or BCC recipients, attach files, and include custom headers. The integration is as simple or sophisticated as your use case requires.Getting StartedSetting up the AutoSend integration takes just a few minutes. Head to your Dodo Payments dashboard, navigate to webhooks, select AutoSend from the integrations list, and enter your API key. If you don't have an AutoSend account yet, you can sign up and get your API key from the dashboard.Full documentation, including code examples and troubleshooting guides, is available at https://docs.dodopayments.com/integrations/autosendLooking ForwardThis partnership represents our commitment to making reliable email infrastructure accessible to every platform that needs it. Dodo Payments customers can now deliver payment communications with the same reliability they bring to payment processing itself.We're here to support you as you roll out the integration. If you have questions or feedback, our team is available through AutoSend's support channels.

Dodo Payments customers can seamlessly integrate AutoSend's email API to handle all payment-related notifications, from transaction confirmations to subscription updates.

AutoSend Partners with Dodo Payments to Power Transactional Email Notifications

When choosing how to send emails from your application, you'll encounter two primary approaches: SMTP (Simple Mail Transfer Protocol) and REST/HTTP APIs. This guide explains both methods, their tradeoffs, and helps you choose the right approach for your use case.<h2>Understanding the Fundamentals</h2><h3>What is SMTP?</h3><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/smtp-simple-mail-transfer-protocol">SMTP</a> is the internet standard protocol for email transmission, established in 1982. When you send an email, whether through Gmail, Outlook, or a programmatic service, SMTP handles the actual delivery between mail servers.How SMTP works:<ol><li>Your application connects to an SMTP server (usually on port 587 for submission or 465 for SSL)</li><li>Authenticates using credentials</li><li>Issues a series of text commands (HELO, MAIL FROM, RCPT TO, DATA)</li><li>Transfers the email content</li><li>Closes the connection</li></ol><h3>What is an Email API?</h3>An <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/transactional-emails">email API</a> is a REST/HTTP interface that abstracts SMTP complexity. Instead of managing protocol-level commands, you make HTTP requests with JSON payloads to send emails.How Email APIs work:<ol><li>Your application makes an HTTP POST request</li><li>Sends email parameters as JSON (to, from, subject, body, attachments)</li><li>The API service handles SMTP communication with receiving servers</li><li>Returns an immediate response with status and metadata</li></ol><h2>Technical Comparison</h2><h3>SMTP Implementation</h3><pre><code class="language-python">import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart

def send_email_smtp(to_email, subject, body):
 smtp_server = "smtp.autosend.com"
 smtp_port = 587
 username = "your_username"
 password = "your_password"
 
 msg = MIMEMultipart()
 msg['From'] = username
 msg['To'] = to_email
 msg['Subject'] = subject
 msg.attach(MIMEText(body, 'plain'))
 
 try:
 server = smtplib.SMTP(smtp_server, smtp_port)
 server.starttls()
 server.login(username, password)
 server.send_message(msg)
 server.quit()
 return True
 except Exception as e:
 print(f"Error: {e}")
 return False
</code></pre><h3>API Implementation</h3><pre><code class="language-python">import requests

def send_email_api(to_email, subject, body):
 api_url = "https://api.autosend.com/v1/send"
 api_key = "your_api_key"
 
 payload = {
 "to": to_email,
 "subject": subject,
 "text": body,
 "from": "sender@example.com"
 }
 
 headers = {
 "Authorization": f"Bearer {api_key}",
 "Content-Type": "application/json"
 }
 
 try:
 response = requests.post(api_url, json=payload, headers=headers)
 response.raise_for_status()
 return response.json()
 except requests.exceptions.RequestException as e:
 print(f"Error: {e}")
 return None
</code></pre><h2>Feature Comparison</h2><h3>Connection Management</h3>SMTP: Requires managing persistent connections or creating new connections for each email. Connection pooling can improve performance but adds complexity.API: Stateless HTTP requests. No connection management needed. HTTP clients handle connection pooling automatically.<h3>Authentication</h3>SMTP: Uses username/password authentication. Some servers support OAuth2, but implementation varies.API: Typically uses API keys or tokens in HTTP headers. More straightforward to implement and rotate credentials.<h3>Error Handling</h3>SMTP: Returns SMTP status codes (250 for success, 550 for rejection, etc.). Error messages can be cryptic and require parsing server responses.<pre><code>550 5.1.1 &lt;user@example.com&gt;: Recipient address rejected
</code></pre>API: Returns structured JSON with clear error messages, error codes, and often includes request IDs for debugging.<pre><code class="language-json">{
 "error": "invalid_recipient",
 "message": "The email address is not valid",
 "request_id": "req_abc123"
}
</code></pre><h3>Rich Features</h3>SMTP: Limited to basic email sending. Advanced features require custom headers or complex MIME construction.API: Built-in support for:<ul><li>Templating</li><li>Scheduled sending</li><li>Analytics and tracking</li><li>Attachment handling via URLs</li><li>Webhook notifications</li><li>Batch sending</li></ul><h3>Rate Limiting and Throttling</h3>SMTP: Often enforced but not transparent. You discover limits when connections are rejected or throttled.API: Clearly documented rate limits. HTTP headers often include remaining quota (<code>X-RateLimit-Remaining</code>).<h3>Debugging and Observability</h3>SMTP: Limited visibility. Must parse logs and SMTP responses. Difficult to trace individual emails.API: Request IDs, detailed logs, dashboard analytics, and webhook events provide comprehensive visibility.<h2>Performance Considerations</h2><h3>Latency</h3>SMTP:<ul><li>Connection setup: 100-500ms (TCP + TLS handshake)</li><li>Authentication: 50-200ms</li><li>Email transmission: 50-300ms</li><li>Total per email: 200-1000ms</li></ul>With connection reuse, subsequent emails: 50-300ms each.API:<ul><li>HTTP request: 100-500ms (including TLS)</li><li>Total per email: 100-500ms</li></ul>APIs are often faster for single emails due to optimized infrastructure.<h3>Throughput</h3>SMTP: Can send multiple emails over a single connection (pipelining). Ideal for high-volume batch sending when implemented correctly.API: Limited by HTTP request overhead, but easier to parallelize. Most services support batch endpoints for sending multiple emails in one request.<h3>Resource Usage</h3>SMTP: Lower bandwidth for multiple emails on same connection. More CPU for managing connections.API: Slightly higher bandwidth due to HTTP overhead. Lower CPU due to simpler implementation.<h2>Security Comparison</h2><h3>Transport Security</h3>SMTP:<ul><li>STARTTLS (port 587): Upgrades connection to TLS</li><li>Implicit TLS (port 465): TLS from connection start</li><li>Requires proper certificate validation</li></ul>API:<ul><li>Always uses HTTPS (TLS 1.2+)</li><li>Certificate validation handled by HTTP client</li><li>More foolproof for developers</li></ul><h3>Credential Exposure</h3>SMTP: Username/password transmitted during authentication. If connection isn't encrypted, credentials can be intercepted.API: API keys in HTTPS headers. Less vulnerable to credential stuffing attacks. Easier to implement key rotation.<h3>Access Control</h3>SMTP: Typically all-or-nothing access to send emails.API: Granular permissions. Different API keys for different environments or applications. Can restrict by IP, domain, or feature.<h2>Use Case Recommendations</h2><h3>Choose SMTP When:</h3><ol><li>High-volume batch sending: Sending thousands of emails in short bursts where connection reuse matters</li><li>Legacy system integration: Working with older systems that only support SMTP</li><li>Self-hosted infrastructure: Running your own mail server</li><li>Protocol requirements: Specific SMTP features or server-to-server communication needed</li><li>Cost sensitivity: Some SMTP relay services are cheaper at high volumes</li></ol><h3>Choose API When:</h3><ol><li>Modern application development: Building new applications or microservices</li><li>Need advanced features: Templates, scheduling, analytics, webhooks</li><li>Developer experience priority: Faster implementation and easier debugging</li><li>Dynamic content: Frequently changing email content, personalization</li><li>Multi-channel communication: Email is one of several notification channels</li></ol><h2>Hybrid Approach</h2>Many email services offer both SMTP and API access. Consider using both:<ul><li>SMTP for high-volume transactional emails (receipts, notifications)</li><li>API for marketing campaigns, complex templates, or emails requiring tracking</li></ul><h2>Migration Considerations</h2><h3>Moving from SMTP to API</h3>Benefits:<ul><li>Simpler codebase</li><li>Better error handling</li><li>Access to advanced features</li></ul>Challenges:<ul><li>API rate limits may differ from SMTP limits</li><li>Need to update all sending code</li><li>Testing in staging environment required</li></ul><h3>Moving from API to SMTP</h3>Benefits:<ul><li>Greater control over email delivery</li><li>Potentially lower costs at scale</li><li>No vendor lock-in to specific API format</li></ul>Challenges:<ul><li>More complex error handling</li><li>Need to implement retry logic</li><li>Connection management overhead</li></ul><h2>Deliverability Considerations</h2>Both SMTP and APIs ultimately deliver via SMTP to recipient servers. Deliverability depends on:<ol><li>Sender reputation: Your domain and IP reputation</li><li>Email authentication: <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/spf-sender-policy-framework">SPF</a>, <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/dkim-domainkeys-identified-mail">DKIM</a>, <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/dmarc-domain-based-message-authentication-reporting-conformance">DMARC</a> configuration</li><li>Content quality: Avoiding spam triggers</li><li>Recipient engagement: Open rates, spam complaints</li></ol>The sending method (SMTP vs API) doesn't directly impact deliverability, but APIs often provide better tools for monitoring and improving it.<h2>Code Examples: Common Scenarios</h2><h3>Sending with Attachments</h3>SMTP:<pre><code class="language-python">from email.mime.base import MIMEBase
from email import encoders

msg = MIMEMultipart()
# ... set headers ...

with open("document.pdf", "rb") as f:
 part = MIMEBase("application", "pdf")
 part.set_payload(f.read())
 encoders.encode_base64(part)
 part.add_header("Content-Disposition", "attachment; filename=document.pdf")
 msg.attach(part)
</code></pre>API:<pre><code class="language-python">import base64

with open("document.pdf", "rb") as f:
 encoded = base64.b64encode(f.read()).decode()

payload = {
 "to": "recipient@example.com",
 "subject": "Document attached",
 "text": "Please see attached",
 "attachments": [{
 "filename": "document.pdf",
 "content": encoded,
 "type": "application/pdf"
 }]
}
</code></pre><h3>Sending HTML Emails</h3>SMTP:<pre><code class="language-python">from email.mime.text import MIMEText

html = """
&lt;html&gt;
 &lt;body&gt;
 &lt;h1&gt;Welcome!&lt;/h1&gt;
 &lt;p&gt;Thanks for signing up.&lt;/p&gt;
 &lt;/body&gt;
&lt;/html&gt;
"""

msg = MIMEMultipart('alternative')
msg.attach(MIMEText("Welcome! Thanks for signing up.", 'plain'))
msg.attach(MIMEText(html, 'html'))
</code></pre>API:<pre><code class="language-python">payload = {
 "to": "recipient@example.com",
 "subject": "Welcome",
 "text": "Welcome! Thanks for signing up.",
 "html": "&lt;h1&gt;Welcome!&lt;/h1&gt;&lt;p&gt;Thanks for signing up.&lt;/p&gt;"
}
</code></pre><h2>Cost Analysis</h2><h3>SMTP Services (typical pricing):</h3><ul><li>Low volume (0-10K/month): Often free</li><li>Medium volume (10K-100K/month): $10-50/month</li><li>High volume (100K-1M/month): $50-200/month</li></ul><h3>API Services (typical pricing):</h3><ul><li>Low volume (0-10K/month): $0-15/month</li><li>Medium volume (10K-100K/month): $15-80/month</li><li>High volume (100K-1M/month): $80-300/month</li></ul>API services typically cost 20-50% more but include additional features that might require separate tools with SMTP-only services.<h2>Monitoring and Logging</h2><h3>SMTP Monitoring</h3><pre><code class="language-python">import logging

logging.basicConfig(level=logging.DEBUG)
logger = logging.getLogger('smtp')

server = smtplib.SMTP(smtp_server, smtp_port)
server.set_debuglevel(1) # Enable debug output
</code></pre>Debug output shows protocol-level communication but requires parsing for structured logging.<h3>API Monitoring</h3><pre><code class="language-python">response = requests.post(api_url, json=payload, headers=headers)
log_data = {
 "email_id": response.json().get("id"),
 "status": response.status_code,
 "recipient": payload["to"],
 "timestamp": datetime.now().isoformat()
}
logger.info("Email sent", extra=log_data)
</code></pre>Structured JSON responses integrate naturally with logging systems.<h2>Reliability and Retry Strategies</h2><h3>SMTP Retry Logic</h3><pre><code class="language-python">import time

def send_with_retry(to_email, subject, body, max_retries=3):
 for attempt in range(max_retries):
 try:
 return send_email_smtp(to_email, subject, body)
 except smtplib.SMTPException as e:
 if attempt == max_retries - 1:
 raise
 wait_time = 2 ** attempt # Exponential backoff
 time.sleep(wait_time)
</code></pre><h3>API Retry Logic</h3>Most HTTP libraries have built-in retry mechanisms:<pre><code class="language-python">from requests.adapters import HTTPAdapter
from urllib3.util.retry import Retry

session = requests.Session()
retry = Retry(
 total=3,
 backoff_factor=1,
 status_forcelist=[429, 500, 502, 503, 504]
)
adapter = HTTPAdapter(max_retries=retry)
session.mount('https://', adapter)
</code></pre><h2>Testing Strategies</h2><h3>SMTP Testing</h3><pre><code class="language-python">import smtplib
from unittest.mock import Mock, patch

def test_email_sending():
 with patch('smtplib.SMTP') as mock_smtp:
 mock_server = Mock()
 mock_smtp.return_value = mock_server
 
 send_email_smtp("test@example.com", "Test", "Body")
 
 mock_server.starttls.assert_called_once()
 mock_server.login.assert_called_once()
 mock_server.send_message.assert_called_once()
</code></pre><h3>API Testing</h3><pre><code class="language-python">import responses

@responses.activate
def test_email_api():
 responses.add(
 responses.POST,
 'https://api.emailservice.com/v1/send',
 json={"id": "msg_123", "status": "queued"},
 status=200
 )
 
 result = send_email_api("test@example.com", "Test", "Body")
 assert result["id"] == "msg_123"
</code></pre>API testing is generally simpler with HTTP mocking libraries.<h2>Decision Framework</h2>Ask yourself these questions:<ol><li>What's your email volume?<ul><li>&lt; 1,000/month: Either works, API is easier</li><li>1,000-100,000/month: Either works well</li><li>100,000/month: Consider SMTP for cost efficiency</li></ul></li><li>What features do you need?<ul><li>Basic sending only: SMTP sufficient</li><li>Templates, analytics, webhooks: API preferred</li></ul></li><li>What's your team's expertise?<ul><li>Comfortable with HTTP/REST: API</li><li>Experienced with mail servers: SMTP</li></ul></li><li>What's your infrastructure?<ul><li>Cloud-native/microservices: API</li><li>Traditional server setup: Either</li></ul></li><li>How important is developer velocity?<ul><li>Critical: API</li><li>Not a priority: Either</li></ul></li></ol><h2>Final thoughts</h2>Neither SMTP nor APIs are universally better. The right choice depends on your specific requirements:<ul><li>Choose SMTP if you need maximum control, have high volumes, or work with legacy systems</li><li>Choose API if you want faster development, better debugging, or advanced features</li><li>Use both if you have different types of emails with different requirements</li></ul>Most modern applications benefit from starting with an API for ease of use, then potentially adding SMTP for high-volume use cases as they scale.The email service provider you choose matters more than the protocol. Look for providers offering both options, strong deliverability, good documentation, and responsive support.

When choosing how to send emails from your application, you'll encounter two primary approaches: SMTP (Simple Mail Transfer Protocol) and REST/HTTP APIs. This guide explains both methods, their tradeoffs, and helps you choose the right approach for your use case.Understanding the FundamentalsWhat is SMTP?SMTP is the internet standard protocol for email transmission, established in 1982. When you send an email, whether through Gmail, Outlook, or a programmatic service, SMTP handles the actual delivery between mail servers.How SMTP works:Your application connects to an SMTP server (usually on port 587 for submission or 465 for SSL)Authenticates using credentialsIssues a series of text commands (HELO, MAIL FROM, RCPT TO, DATA)Transfers the email contentCloses the connectionWhat is an Email API?An email API is a REST/HTTP interface that abstracts SMTP complexity. Instead of managing protocol-level commands, you make HTTP requests with JSON payloads to send emails.How Email APIs work:Your application makes an HTTP POST requestSends email parameters as JSON (to, from, subject, body, attachments)The API service handles SMTP communication with receiving serversReturns an immediate response with status and metadataTechnical ComparisonSMTP Implementationimport smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart

def send_email_smtp(to_email, subject, body):
 smtp_server = "smtp.autosend.com"
 smtp_port = 587
 username = "your_username"
 password = "your_password"
 
 msg = MIMEMultipart()
 msg['From'] = username
 msg['To'] = to_email
 msg['Subject'] = subject
 msg.attach(MIMEText(body, 'plain'))
 
 try:
 server = smtplib.SMTP(smtp_server, smtp_port)
 server.starttls()
 server.login(username, password)
 server.send_message(msg)
 server.quit()
 return True
 except Exception as e:
 print(f"Error: {e}")
 return False
API Implementationimport requests

def send_email_api(to_email, subject, body):
 api_url = "https://api.autosend.com/v1/send"
 api_key = "your_api_key"
 
 payload = {
 "to": to_email,
 "subject": subject,
 "text": body,
 "from": "sender@example.com"
 }
 
 headers = {
 "Authorization": f"Bearer {api_key}",
 "Content-Type": "application/json"
 }
 
 try:
 response = requests.post(api_url, json=payload, headers=headers)
 response.raise_for_status()
 return response.json()
 except requests.exceptions.RequestException as e:
 print(f"Error: {e}")
 return None
Feature ComparisonConnection ManagementSMTP: Requires managing persistent connections or creating new connections for each email. Connection pooling can improve performance but adds complexity.API: Stateless HTTP requests. No connection management needed. HTTP clients handle connection pooling automatically.AuthenticationSMTP: Uses username/password authentication. Some servers support OAuth2, but implementation varies.API: Typically uses API keys or tokens in HTTP headers. More straightforward to implement and rotate credentials.Error HandlingSMTP: Returns SMTP status codes (250 for success, 550 for rejection, etc.). Error messages can be cryptic and require parsing server responses.550 5.1.1 &lt;user@example.com&gt;: Recipient address rejected
API: Returns structured JSON with clear error messages, error codes, and often includes request IDs for debugging.{
 "error": "invalid_recipient",
 "message": "The email address is not valid",
 "request_id": "req_abc123"
}
Rich FeaturesSMTP: Limited to basic email sending. Advanced features require custom headers or complex MIME construction.API: Built-in support for:TemplatingScheduled sendingAnalytics and trackingAttachment handling via URLsWebhook notificationsBatch sendingRate Limiting and ThrottlingSMTP: Often enforced but not transparent. You discover limits when connections are rejected or throttled.API: Clearly documented rate limits. HTTP headers often include remaining quota (X-RateLimit-Remaining).Debugging and ObservabilitySMTP: Limited visibility. Must parse logs and SMTP responses. Difficult to trace individual emails.API: Request IDs, detailed logs, dashboard analytics, and webhook events provide comprehensive visibility.Performance ConsiderationsLatencySMTP:Connection setup: 100-500ms (TCP + TLS handshake)Authentication: 50-200msEmail transmission: 50-300msTotal per email: 200-1000msWith connection reuse, subsequent emails: 50-300ms each.API:HTTP request: 100-500ms (including TLS)Total per email: 100-500msAPIs are often faster for single emails due to optimized infrastructure.ThroughputSMTP: Can send multiple emails over a single connection (pipelining). Ideal for high-volume batch sending when implemented correctly.API: Limited by HTTP request overhead, but easier to parallelize. Most services support batch endpoints for sending multiple emails in one request.Resource UsageSMTP: Lower bandwidth for multiple emails on same connection. More CPU for managing connections.API: Slightly higher bandwidth due to HTTP overhead. Lower CPU due to simpler implementation.Security ComparisonTransport SecuritySMTP:STARTTLS (port 587): Upgrades connection to TLSImplicit TLS (port 465): TLS from connection startRequires proper certificate validationAPI:Always uses HTTPS (TLS 1.2+)Certificate validation handled by HTTP clientMore foolproof for developersCredential ExposureSMTP: Username/password transmitted during authentication. If connection isn't encrypted, credentials can be intercepted.API: API keys in HTTPS headers. Less vulnerable to credential stuffing attacks. Easier to implement key rotation.Access ControlSMTP: Typically all-or-nothing access to send emails.API: Granular permissions. Different API keys for different environments or applications. Can restrict by IP, domain, or feature.Use Case RecommendationsChoose SMTP When:High-volume batch sending: Sending thousands of emails in short bursts where connection reuse mattersLegacy system integration: Working with older systems that only support SMTPSelf-hosted infrastructure: Running your own mail serverProtocol requirements: Specific SMTP features or server-to-server communication neededCost sensitivity: Some SMTP relay services are cheaper at high volumesChoose API When:Modern application development: Building new applications or microservicesNeed advanced features: Templates, scheduling, analytics, webhooksDeveloper experience priority: Faster implementation and easier debuggingDynamic content: Frequently changing email content, personalizationMulti-channel communication: Email is one of several notification channelsHybrid ApproachMany email services offer both SMTP and API access. Consider using both:SMTP for high-volume transactional emails (receipts, notifications)API for marketing campaigns, complex templates, or emails requiring trackingMigration ConsiderationsMoving from SMTP to APIBenefits:Simpler codebaseBetter error handlingAccess to advanced featuresChallenges:API rate limits may differ from SMTP limitsNeed to update all sending codeTesting in staging environment requiredMoving from API to SMTPBenefits:Greater control over email deliveryPotentially lower costs at scaleNo vendor lock-in to specific API formatChallenges:More complex error handlingNeed to implement retry logicConnection management overheadDeliverability ConsiderationsBoth SMTP and APIs ultimately deliver via SMTP to recipient servers. Deliverability depends on:Sender reputation: Your domain and IP reputationEmail authentication: SPF, DKIM, DMARC configurationContent quality: Avoiding spam triggersRecipient engagement: Open rates, spam complaintsThe sending method (SMTP vs API) doesn't directly impact deliverability, but APIs often provide better tools for monitoring and improving it.Code Examples: Common ScenariosSending with AttachmentsSMTP:from email.mime.base import MIMEBase
from email import encoders

msg = MIMEMultipart()
# ... set headers ...

with open("document.pdf", "rb") as f:
 part = MIMEBase("application", "pdf")
 part.set_payload(f.read())
 encoders.encode_base64(part)
 part.add_header("Content-Disposition", "attachment; filename=document.pdf")
 msg.attach(part)
API:import base64

with open("document.pdf", "rb") as f:
 encoded = base64.b64encode(f.read()).decode()

payload = {
 "to": "recipient@example.com",
 "subject": "Document attached",
 "text": "Please see attached",
 "attachments": [{
 "filename": "document.pdf",
 "content": encoded,
 "type": "application/pdf"
 }]
}
Sending HTML EmailsSMTP:from email.mime.text import MIMEText

html = """
&lt;html&gt;
 &lt;body&gt;
 &lt;h1&gt;Welcome!&lt;/h1&gt;
 &lt;p&gt;Thanks for signing up.&lt;/p&gt;
 &lt;/body&gt;
&lt;/html&gt;
"""

msg = MIMEMultipart('alternative')
msg.attach(MIMEText("Welcome! Thanks for signing up.", 'plain'))
msg.attach(MIMEText(html, 'html'))
API:payload = {
 "to": "recipient@example.com",
 "subject": "Welcome",
 "text": "Welcome! Thanks for signing up.",
 "html": "&lt;h1&gt;Welcome!&lt;/h1&gt;&lt;p&gt;Thanks for signing up.&lt;/p&gt;"
}
Cost AnalysisSMTP Services (typical pricing):Low volume (0-10K/month): Often freeMedium volume (10K-100K/month): $10-50/monthHigh volume (100K-1M/month): $50-200/monthAPI Services (typical pricing):Low volume (0-10K/month): $0-15/monthMedium volume (10K-100K/month): $15-80/monthHigh volume (100K-1M/month): $80-300/monthAPI services typically cost 20-50% more but include additional features that might require separate tools with SMTP-only services.Monitoring and LoggingSMTP Monitoringimport logging

logging.basicConfig(level=logging.DEBUG)
logger = logging.getLogger('smtp')

server = smtplib.SMTP(smtp_server, smtp_port)
server.set_debuglevel(1) # Enable debug output
Debug output shows protocol-level communication but requires parsing for structured logging.API Monitoringresponse = requests.post(api_url, json=payload, headers=headers)
log_data = {
 "email_id": response.json().get("id"),
 "status": response.status_code,
 "recipient": payload["to"],
 "timestamp": datetime.now().isoformat()
}
logger.info("Email sent", extra=log_data)
Structured JSON responses integrate naturally with logging systems.Reliability and Retry StrategiesSMTP Retry Logicimport time

def send_with_retry(to_email, subject, body, max_retries=3):
 for attempt in range(max_retries):
 try:
 return send_email_smtp(to_email, subject, body)
 except smtplib.SMTPException as e:
 if attempt == max_retries - 1:
 raise
 wait_time = 2 ** attempt # Exponential backoff
 time.sleep(wait_time)
API Retry LogicMost HTTP libraries have built-in retry mechanisms:from requests.adapters import HTTPAdapter
from urllib3.util.retry import Retry

session = requests.Session()
retry = Retry(
 total=3,
 backoff_factor=1,
 status_forcelist=[429, 500, 502, 503, 504]
)
adapter = HTTPAdapter(max_retries=retry)
session.mount('https://', adapter)
Testing StrategiesSMTP Testingimport smtplib
from unittest.mock import Mock, patch

def test_email_sending():
 with patch('smtplib.SMTP') as mock_smtp:
 mock_server = Mock()
 mock_smtp.return_value = mock_server
 
 send_email_smtp("test@example.com", "Test", "Body")
 
 mock_server.starttls.assert_called_once()
 mock_server.login.assert_called_once()
 mock_server.send_message.assert_called_once()
API Testingimport responses

@responses.activate
def test_email_api():
 responses.add(
 responses.POST,
 'https://api.emailservice.com/v1/send',
 json={"id": "msg_123", "status": "queued"},
 status=200
 )
 
 result = send_email_api("test@example.com", "Test", "Body")
 assert result["id"] == "msg_123"
API testing is generally simpler with HTTP mocking libraries.Decision FrameworkAsk yourself these questions:What's your email volume?&lt; 1,000/month: Either works, API is easier1,000-100,000/month: Either works well100,000/month: Consider SMTP for cost efficiencyWhat features do you need?Basic sending only: SMTP sufficientTemplates, analytics, webhooks: API preferredWhat's your team's expertise?Comfortable with HTTP/REST: APIExperienced with mail servers: SMTPWhat's your infrastructure?Cloud-native/microservices: APITraditional server setup: EitherHow important is developer velocity?Critical: APINot a priority: EitherFinal thoughtsNeither SMTP nor APIs are universally better. The right choice depends on your specific requirements:Choose SMTP if you need maximum control, have high volumes, or work with legacy systemsChoose API if you want faster development, better debugging, or advanced featuresUse both if you have different types of emails with different requirementsMost modern applications benefit from starting with an API for ease of use, then potentially adding SMTP for high-volume use cases as they scale.The email service provider you choose matters more than the protocol. Look for providers offering both options, strong deliverability, good documentation, and responsive support.

Complete technical guide comparing SMTP vs API for sending emails. Includes code examples, performance benchmarks, and decision framework for developers.

SMTP vs API: Complete Developer Guide

Every week someone asks me why AutoSend doesn’t have a free plan. Now it's getting so frequent that I decided to write it down. It’s a fair question though, so here’s the honest answer I can finally link to. This isn’t a justification, but the reasoning behind a decision we thought about deeply.Every new product seems to start with a free plan. It’s almost a default pricing strategy now. You launch, make it free for a while, get signups, figure out conversion later. It sounds like a smart growth hack, and for some products, it probably is.When we started building AutoSend, we thought about it too. The logic was simple: lower the entry barrier, attract more users, get feedback faster. But the more we discussed it, the less sense it made.AutoSend isn’t just another SaaS company. Every user shares the same sending infrastructure like IPs, reputation, and deliverability. In email, those things are sacred. If one sender messes up, everyone pays the price. The last thing we wanted was someone using a free plan to test random data or spam their way through Gmail, dragging everyone else down with them.Deliverability is fragile. It’s built on trust, consistency, and good behavior. And those things are challenging to enforce with a free plan. So the decision became less about revenue and more about protecting deliverability for everyone who depends on AutoSend to reach inboxes every single time.Removing the idea of a free plan early gave us clarity. It forced us to build for paying customers from the start. It made the roadmap simpler, the priorities sharper, and the product stronger.There’s also the question of sustainability. AutoSend isn’t a side project. It’s something we plan to run for years. If we’re going to invest in infrastructure, support, integrations, and scale, we need to build on a foundation where paying users are the nucleus, not an afterthought.Yogini and I actually asked ourselves one simple question during our brainstorming session: do we want a popular product or a sustainable business? The answer was the latter.So we made the call. Not because we’re against free users, but because we’re for focus and long-term value. We’d rather serve fewer customers deeply than chase signups that churn.For us, ditching the free plan was a commitment to quality, reliability, and trust which are extremely important for an email service provider. And that’s exactly the kind of product we want AutoSend to be!<hr><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/pricing">AutoSend pricing</a> starts with a $1 Hobby plan for transactional emails and a $5 plan for marketing + transactional emails. All Pro plans begin at $10, with every feature included and generous limits.Unlike most providers, AutoSend charges by the number of emails you send, not how many subscribers you store, making it one of the simplest and fairest pricing models out there.

Every week someone asks me why AutoSend doesn’t have a free plan. Now it's getting so frequent that I decided to write it down. It’s a fair question though, so here’s the honest answer I can finally link to. This isn’t a justification, but the reasoning behind a decision we thought about deeply.Every new product seems to start with a free plan. It’s almost a default pricing strategy now. You launch, make it free for a while, get signups, figure out conversion later. It sounds like a smart growth hack, and for some products, it probably is.When we started building AutoSend, we thought about it too. The logic was simple: lower the entry barrier, attract more users, get feedback faster. But the more we discussed it, the less sense it made.AutoSend isn’t just another SaaS company. Every user shares the same sending infrastructure like IPs, reputation, and deliverability. In email, those things are sacred. If one sender messes up, everyone pays the price. The last thing we wanted was someone using a free plan to test random data or spam their way through Gmail, dragging everyone else down with them.Deliverability is fragile. It’s built on trust, consistency, and good behavior. And those things are challenging to enforce with a free plan. So the decision became less about revenue and more about protecting deliverability for everyone who depends on AutoSend to reach inboxes every single time.Removing the idea of a free plan early gave us clarity. It forced us to build for paying customers from the start. It made the roadmap simpler, the priorities sharper, and the product stronger.There’s also the question of sustainability. AutoSend isn’t a side project. It’s something we plan to run for years. If we’re going to invest in infrastructure, support, integrations, and scale, we need to build on a foundation where paying users are the nucleus, not an afterthought.Yogini and I actually asked ourselves one simple question during our brainstorming session: do we want a popular product or a sustainable business? The answer was the latter.So we made the call. Not because we’re against free users, but because we’re for focus and long-term value. We’d rather serve fewer customers deeply than chase signups that churn.For us, ditching the free plan was a commitment to quality, reliability, and trust which are extremely important for an email service provider. And that’s exactly the kind of product we want AutoSend to be!AutoSend pricing starts with a $1 Hobby plan for transactional emails and a $5 plan for marketing + transactional emails. All Pro plans begin at $10, with every feature included and generous limits.Unlike most providers, AutoSend charges by the number of emails you send, not how many subscribers you store, making it one of the simplest and fairest pricing models out there.

How protecting deliverability, reliability, and focus shaped our decision to not offer the free plan.

Why AutoSend Doesn’t Have a Free Plan

Every email you send has a cost. Not just in dollars, but in reputation, trust, and opportunity. When emails fail to reach the inbox, it’s not just a technical issue. It silently erodes the connection between your product and your users.Most teams only notice deliverability when open rates drop or transactional emails stop working. But by then, the damage is already done. Poor deliverability doesn’t just waste money; it weakens everything that makes your email channel valuable.<h2>What Poor Deliverability Really Means</h2>Email deliverability is the percentage of emails that successfully reach the recipient’s inbox. You might still see a 100 percent “sent” rate in your dashboard, but that doesn’t mean users actually received your message.Poor deliverability can mean:<ul><li>Emails landing in the spam or promotions folder.</li><li>Delays in critical transactional emails like password resets.</li><li>Emails being blocked entirely by ISPs.</li><li>A gradual loss of trust from mailbox providers.</li></ul>In short, it means your emails are being treated as noise instead of value.<h2>The Cost in Lost Engagement</h2>When legitimate emails end up in spam, your users stop opening them. Lower engagement signals mailbox providers that your domain is untrustworthy, which makes future emails even less likely to be delivered.If you’re sending transactional emails like password resets or verification codes, this isn’t just an inconvenience. It directly impacts user experience. A single undelivered verification email can mean a lost sign-up or a failed purchase.You can read our detailed guide on <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/blog/do-transactional-emails-need-an-unsubscribe-link">Do Transactional Emails Need an Unsubscribe Link?</a> to understand how compliance and deliverability work together.<h2>The Cost in Brand Reputation</h2>Users judge your reliability based on whether they receive your emails on time. If they don’t, it reflects poorly on your product, even if the problem lies in technical configuration.A brand that can’t deliver its own system emails quickly loses credibility. Over time, this perception affects retention, referrals, and customer satisfaction.Poor deliverability also hurts domain reputation. Providers like Gmail track your sending patterns, complaint rates, and engagement levels. Once your domain is flagged as risky, even your most loyal customers might stop seeing your messages altogether.<h2>The Cost in Revenue and Growth</h2>For SaaS and e-commerce companies, email drives user activation, retention, and payments. Every failed delivery can mean missed conversions, abandoned carts, or unpaid invoices.Even marketing emails with great copy and design are useless if they never reach the inbox. Imagine spending hours crafting campaigns only for them to end up filtered out of sight.If you’re building a new email strategy, it’s worth reading <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/blog/how-spf-dkim-and-dmarc-work">How SPF, DKIM, and DMARC Work Together to Protect Your Domain</a> to make sure your authentication setup is correct from the start.<h2>The Cost in Compliance Risk</h2>Mailbox providers and privacy laws expect senders to maintain transparent and secure practices. If your authentication is misconfigured or missing, your domain becomes vulnerable to spoofing or phishing attempts.Users who receive fake emails appearing to be from your brand are more likely to lose trust or report messages as spam. Over time, this can trigger blocks or penalties from major ISPs.You can further protect your brand identity by setting up <a target="_new" rel="noopener" class="break-all link-break text-gray-500 hover:underline decorated-link" href="https://autosend.com/blog/how-to-get-a-verified-checkmark-in-gmail-with-bimi">BIMI verification</a>, which allows your verified logo to appear next to your emails in inboxes like Gmail and Yahoo Mail.<h2>How to Fix Deliverability Before It Hurts You</h2>Improving deliverability is not about sending fewer emails. It’s about sending the right emails, from a trusted domain, to the right audience.Here are a few things every team should do:<ul><li>Authenticate your domain with <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/spf-sender-policy-framework">SPF</a>, <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/dkim-domainkeys-identified-mail">DKIM</a>, and <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/dmarc-domain-based-message-authentication-reporting-conformance">DMARC</a>.</li><li>Use consistent “From” addresses and reply-to fields.</li><li>Monitor bounce and complaint rates regularly.</li><li>Keep your sending reputation healthy by cleaning inactive lists.</li><li>Send only relevant, user-initiated messages.</li><li>Choose an <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/email-service-provider-esp">ESP</a> that prioritizes deliverability and transparency.</li></ul>AutoSend was built with these principles in mind. We handle the complexity of deliverability so you can focus on building your product. Every message sent through AutoSend is authenticated, monitored, and optimized for inbox placement.<hr>Deliverability is not a metric you check once; it’s an ongoing trust signal between your domain and your users. If your emails are delayed, blocked, or lost in spam, you’re not just missing metrics then you’re missing moments of user retention.Investing in deliverability early is cheaper than repairing reputation later. Make sure your domain is authenticated, your templates are compliant, and your <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/email-service-provider-esp">ESP</a> actually cares about your inbox health.Because every missed email is a missed opportunity.

Every email you send has a cost. Not just in dollars, but in reputation, trust, and opportunity. When emails fail to reach the inbox, it’s not just a technical issue. It silently erodes the connection between your product and your users.Most teams only notice deliverability when open rates drop or transactional emails stop working. But by then, the damage is already done. Poor deliverability doesn’t just waste money; it weakens everything that makes your email channel valuable.What Poor Deliverability Really MeansEmail deliverability is the percentage of emails that successfully reach the recipient’s inbox. You might still see a 100 percent “sent” rate in your dashboard, but that doesn’t mean users actually received your message.Poor deliverability can mean:Emails landing in the spam or promotions folder.Delays in critical transactional emails like password resets.Emails being blocked entirely by ISPs.A gradual loss of trust from mailbox providers.In short, it means your emails are being treated as noise instead of value.The Cost in Lost EngagementWhen legitimate emails end up in spam, your users stop opening them.Lower engagement signals mailbox providers that your domain is untrustworthy, which makes future emails even less likely to be delivered.If you’re sending transactional emails like password resets or verification codes, this isn’t just an inconvenience. It directly impacts user experience. A single undelivered verification email can mean a lost sign-up or a failed purchase.You can read our detailed guide on Do Transactional Emails Need an Unsubscribe Link? to understand how compliance and deliverability work together.The Cost in Brand ReputationUsers judge your reliability based on whether they receive your emails on time.If they don’t, it reflects poorly on your product, even if the problem lies in technical configuration.A brand that can’t deliver its own system emails quickly loses credibility. Over time, this perception affects retention, referrals, and customer satisfaction.Poor deliverability also hurts domain reputation. Providers like Gmail track your sending patterns, complaint rates, and engagement levels. Once your domain is flagged as risky, even your most loyal customers might stop seeing your messages altogether.The Cost in Revenue and GrowthFor SaaS and e-commerce companies, email drives user activation, retention, and payments. Every failed delivery can mean missed conversions, abandoned carts, or unpaid invoices.Even marketing emails with great copy and design are useless if they never reach the inbox. Imagine spending hours crafting campaigns only for them to end up filtered out of sight.If you’re building a new email strategy, it’s worth reading How SPF, DKIM, and DMARC Work Together to Protect Your Domain to make sure your authentication setup is correct from the start.The Cost in Compliance RiskMailbox providers and privacy laws expect senders to maintain transparent and secure practices. If your authentication is misconfigured or missing, your domain becomes vulnerable to spoofing or phishing attempts.Users who receive fake emails appearing to be from your brand are more likely to lose trust or report messages as spam. Over time, this can trigger blocks or penalties from major ISPs.You can further protect your brand identity by setting up BIMI verification, which allows your verified logo to appear next to your emails in inboxes like Gmail and Yahoo Mail.How to Fix Deliverability Before It Hurts YouImproving deliverability is not about sending fewer emails. It’s about sending the right emails, from a trusted domain, to the right audience.Here are a few things every team should do:Authenticate your domain with SPF, DKIM, and DMARC.Use consistent “From” addresses and reply-to fields.Monitor bounce and complaint rates regularly.Keep your sending reputation healthy by cleaning inactive lists.Send only relevant, user-initiated messages.Choose an ESP that prioritizes deliverability and transparency.AutoSend was built with these principles in mind. We handle the complexity of deliverability so you can focus on building your product. Every message sent through AutoSend is authenticated, monitored, and optimized for inbox placement.Deliverability is not a metric you check once; it’s an ongoing trust signal between your domain and your users. If your emails are delayed, blocked, or lost in spam, you’re not just missing metrics then you’re missing moments of user retention.Investing in deliverability early is cheaper than repairing reputation later.Make sure your domain is authenticated, your templates are compliant, and your ESP actually cares about your inbox health.Because every missed email is a missed opportunity.

Poor email deliverability hurts trust, engagement, and revenue. Learn how to protect your domain and improve email deliverability with AutoSend.

The Hidden Cost of Poor Email Deliverability

If you’ve ever received a password reset email or a purchase confirmation, you probably noticed something missing. There’s no unsubscribe link at the bottom.That’s not a mistake. It’s actually the right thing to do.In this article, we’ll explain why most transactional emails don’t require an unsubscribe link, when you might still include one, and how to stay compliant with email laws while keeping your users informed.<h2>What Are Transactional Emails?</h2><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/transactional-emails">Transactional emails</a> are system-generated messages triggered by a user’s action or a specific event. They are not promotional. Their purpose is to deliver important information related to a transaction, account, or product activity.Common examples include:<ul><li>Password reset or account recovery emails.</li><li>Order confirmations and shipping updates.</li><li>Account verification and activation messages.</li><li>Security alerts or login notifications.</li><li>Billing receipts and subscription renewals.</li></ul>These emails are essential to user experience and often contain security, compliance, or time-sensitive information that users must receive.<h2>Why Transactional Emails Usually Don’t Need an Unsubscribe Link</h2>Unlike marketing or promotional emails, transactional emails are functional, not optional. Email regulations around the world make a clear distinction between these two categories.<h3>They Are Triggered by User Actions</h3>The recipient expects these emails. When a user resets a password, verifies an account, or makes a purchase, the email is a direct response to their request. Adding an unsubscribe option would make no sense because the email is necessary to complete their action.<h3>Compliance Rules Recognize the Difference</h3>Under laws like <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://www.ftc.gov/business-guidance/resources/can-spam-act-compliance-guide-business">CAN-SPAM (US)</a>, <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://gdpr.eu/email-encryption/">GDPR (EU)</a>, and <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://ised-isde.canada.ca/site/canada-anti-spam-legislation/en">CASL (Canada)</a>, unsubscribe mechanisms are required only for commercial or promotional messages. Transactional or relationship emails are exempt because they are part of an existing service relationship.<h3>They Contain Critical Information</h3>Transactional emails often include important details such as payment confirmations, security alerts, or compliance notifications. If users could unsubscribe, they might miss information that affects their privacy, security, or account access.<h3>They Build User Trust</h3>A clear, focused transactional email without marketing clutter or unnecessary unsubscribe links reinforces your brand’s reliability. It shows that you only send messages when it truly matters.<h2>When You Should Include an Unsubscribe Option</h2>Even though most transactional emails don’t require an unsubscribe link, there are edge cases where you should consider adding one.<h3>When You Mix Transactional and Promotional Content</h3>If your email contains any marketing message, even a small one, it may be reclassified as a commercial message under CAN-SPAM.For example:<blockquote>“Your password has been reset successfully. By the way, here’s 10% off our new plan.”</blockquote>This turns an otherwise transactional message into a hybrid email, and in that case, you must include an unsubscribe link to stay compliant.<h3>For Optional Product Notifications</h3>Some product updates, reminders, or usage summaries are not strictly required. For example, a weekly account summary or feature announcement may feel transactional but is still promotional in nature.For such emails, an unsubscribe or preference-management link is best practice.<h3>When User Experience Calls for It</h3>Even when not legally required, giving users control over certain email types can improve trust and reduce spam complaints. For example, providing settings to manage notifications (instead of a global unsubscribe) lets users fine-tune communication.<h2>How to Handle Compliance the Right Way</h2>Here’s a simple rule of thumb:<blockquote>If the email is essential to the product’s operation or a user-initiated action, it does not need an unsubscribe link.</blockquote>However, you should still make sure your transactional emails:<ul><li>Clearly identify your organization in the sender name and footer.</li><li>Include a valid reply-to or support address.</li><li>Avoid promotional content or upsells.</li><li>Use consistent branding and tone to avoid confusion.</li><li>Comply with your regional privacy regulations (GDPR, CAN-SPAM, CASL).</li></ul><h2>Example: Proper Transactional Email Footers</h2><h3>Good Example (No Unsubscribe Link)</h3><blockquote>You’re receiving this email because you requested a password reset for your AutoSend account. If you didn’t request this, please contact <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="mailto:support@autosend.com">support@autosend.com</a>.</blockquote><h3>Bad Example (Violates Compliance)</h3><blockquote>You’re receiving this email because you’re part of our community. Also, check out our new pricing plans! [View Plans] No unsubscribe link included.</blockquote>The second example mixes marketing content into a transactional context, which can trigger spam filters and violate regulations.<h2>AutoSend’s Approach to Transactional Emails</h2>At AutoSend, we help developers and teams send secure, compliant, and fast transactional emails. Every email sent through AutoSend is authenticated with SPF, DKIM, and DMARC to ensure deliverability and domain protection.You can customize your templates, include dynamic variables, and design clear footers that follow compliance standards — all without worrying about marketing filters.If you want to take authentication further, you can also set up <a target="_new" rel="noopener" class="break-all link-break text-gray-500 hover:underline decorated-link" href="https://autosend.com/blog/how-to-get-a-verified-checkmark-in-gmail-with-bimi">BIMI (Brand Indicators for Message Identification)</a> to show your verified logo and checkmark in inboxes like Gmail and Yahoo Mail.<hr><h2>TL;DR</h2>Transactional emails do not require an unsubscribe link as long as they:<ul><li>Are triggered by a user action.</li><li>Contain essential product or account information.</li><li>Do not include marketing or promotional content.</li></ul>If you mix marketing messages or optional updates, add an unsubscribe or preference link to stay compliant and user-friendly.

If you’ve ever received a password reset email or a purchase confirmation, you probably noticed something missing. There’s no unsubscribe link at the bottom.That’s not a mistake. It’s actually the right thing to do.In this article, we’ll explain why most transactional emails don’t require an unsubscribe link, when you might still include one, and how to stay compliant with email laws while keeping your users informed.What Are Transactional Emails?Transactional emails are system-generated messages triggered by a user’s action or a specific event. They are not promotional. Their purpose is to deliver important information related to a transaction, account, or product activity.Common examples include:Password reset or account recovery emails.Order confirmations and shipping updates.Account verification and activation messages.Security alerts or login notifications.Billing receipts and subscription renewals.These emails are essential to user experience and often contain security, compliance, or time-sensitive information that users must receive.Why Transactional Emails Usually Don’t Need an Unsubscribe LinkUnlike marketing or promotional emails, transactional emails are functional, not optional. Email regulations around the world make a clear distinction between these two categories.They Are Triggered by User ActionsThe recipient expects these emails. When a user resets a password, verifies an account, or makes a purchase, the email is a direct response to their request.Adding an unsubscribe option would make no sense because the email is necessary to complete their action.Compliance Rules Recognize the DifferenceUnder laws like CAN-SPAM (US), GDPR (EU), and CASL (Canada), unsubscribe mechanisms are required only for commercial or promotional messages.Transactional or relationship emails are exempt because they are part of an existing service relationship.They Contain Critical InformationTransactional emails often include important details such as payment confirmations, security alerts, or compliance notifications.If users could unsubscribe, they might miss information that affects their privacy, security, or account access.They Build User TrustA clear, focused transactional email without marketing clutter or unnecessary unsubscribe links reinforces your brand’s reliability.It shows that you only send messages when it truly matters.When You Should Include an Unsubscribe OptionEven though most transactional emails don’t require an unsubscribe link, there are edge cases where you should consider adding one.When You Mix Transactional and Promotional ContentIf your email contains any marketing message, even a small one, it may be reclassified as a commercial message under CAN-SPAM.For example:“Your password has been reset successfully. By the way, here’s 10% off our new plan.”This turns an otherwise transactional message into a hybrid email, and in that case, you must include an unsubscribe link to stay compliant.For Optional Product NotificationsSome product updates, reminders, or usage summaries are not strictly required.For example, a weekly account summary or feature announcement may feel transactional but is still promotional in nature.For such emails, an unsubscribe or preference-management link is best practice.When User Experience Calls for ItEven when not legally required, giving users control over certain email types can improve trust and reduce spam complaints.For example, providing settings to manage notifications (instead of a global unsubscribe) lets users fine-tune communication.How to Handle Compliance the Right WayHere’s a simple rule of thumb:If the email is essential to the product’s operation or a user-initiated action, it does not need an unsubscribe link.However, you should still make sure your transactional emails:Clearly identify your organization in the sender name and footer.Include a valid reply-to or support address.Avoid promotional content or upsells.Use consistent branding and tone to avoid confusion.Comply with your regional privacy regulations (GDPR, CAN-SPAM, CASL).Example: Proper Transactional Email FootersGood Example (No Unsubscribe Link)You’re receiving this email because you requested a password reset for your AutoSend account.If you didn’t request this, please contact support@autosend.com.Bad Example (Violates Compliance)You’re receiving this email because you’re part of our community.Also, check out our new pricing plans! [View Plans]No unsubscribe link included.The second example mixes marketing content into a transactional context, which can trigger spam filters and violate regulations.AutoSend’s Approach to Transactional EmailsAt AutoSend, we help developers and teams send secure, compliant, and fast transactional emails.Every email sent through AutoSend is authenticated with SPF, DKIM, and DMARC to ensure deliverability and domain protection.You can customize your templates, include dynamic variables, and design clear footers that follow compliance standards — all without worrying about marketing filters.If you want to take authentication further, you can also set up BIMI (Brand Indicators for Message Identification) to show your verified logo and checkmark in inboxes like Gmail and Yahoo Mail.TL;DRTransactional emails do not require an unsubscribe link as long as they:Are triggered by a user action.Contain essential product or account information.Do not include marketing or promotional content.If you mix marketing messages or optional updates, add an unsubscribe or preference link to stay compliant and user-friendly.

Learn when transactional emails need an unsubscribe link, when they don’t, and how to stay compliant with CAN-SPAM and GDPR rules.

Do Transactional Emails Need an Unsubscribe Link?

If your legitimate emails are landing in spam or being spoofed by attackers, your authentication setup might be the problem. To make sure your emails are trusted, you need three essential protocols: SPF, DKIM, and DMARC.These technologies form the foundation of secure email delivery. Together, they prevent phishing, domain impersonation, and spam, ensuring that your messages reach the inbox safely.This guide explains what each protocol does, how they work together, and how to set them up correctly.<h2>Why Email Authentication Matters</h2>Every day, millions of phishing emails are sent pretending to be from legitimate companies. Without proper authentication, spammers can forge your domain name and send fake messages that look real.Strong email authentication:<ul><li>Protects your brand reputation</li><li>Improves deliverability</li><li>Increases user trust</li><li>Prevents unauthorized senders from using your domain</li></ul><h2>What Is SPF?</h2><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/spf-sender-policy-framework">SPF (Sender Policy Framework)</a> is a DNS record that specifies which mail servers are allowed to send emails on behalf of your domain.When an email is received, the receiving mail server checks the sender’s domain and verifies if the sending IP address is listed in the SPF record.If it matches, the SPF check passes. If not, it fails and may be marked as spam or rejected.Example SPF Record<pre><code>v=spf1 include:autosend.com -all
</code></pre>How it works:<ol><li>The receiving mail server extracts the domain from the “Return-Path” header.</li><li>It looks up the SPF record for that domain.</li><li>If the IP address sending the message matches one listed, the email is authenticated.</li></ol>Best Practices for SPF<ul><li>Use <code>-all</code> instead of <code>~all</code> to enforce strict validation.</li><li>Keep the record under 10 DNS lookups to avoid breaking SPF.</li><li>Update it whenever you add or remove an email service.</li></ul><h2>What Is DKIM?</h2><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/dkim-domainkeys-identified-mail">DKIM (DomainKeys Identified Mail)</a> adds a digital signature to your emails to prove that the content has not been modified.Each outgoing email is signed with a private key that only your mail server knows. The recipient can then verify this signature using a public key stored in your domain’s DNS.Example DKIM Record<pre><code>v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0B...
</code></pre>How it works:<ol><li>Your mail server generates a DKIM signature and attaches it to each email header.</li><li>The receiving server fetches the public key from your DNS.</li><li>It verifies the signature to ensure that the email body and headers were not altered.</li></ol>Best Practices for DKIM<ul><li>Use at least a 2048-bit key for stronger security.</li><li>Rotate DKIM keys periodically (every 6–12 months).</li><li>Ensure your “From” domain matches the signing domain for alignment with DMARC.</li></ul><h2>What Is DMARC?</h2><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/dmarc-domain-based-message-authentication-reporting-conformance">DMARC (Domain-based Message Authentication, Reporting, and Conformance)</a> ties SPF and DKIM together and defines what to do when an email fails authentication.DMARC allows you to tell receiving servers how to handle unauthenticated messages (none, quarantine, or reject) and provides detailed reports on who is sending emails using your domain.Example DMARC Record<pre><code>v=DMARC1; p=quarantine; rua=mailto:dmarc-reports@yourdomain.com; adkim=s; aspf=s
</code></pre>How it works:<ol><li>The receiving server checks if the email passes SPF or DKIM.</li><li>It verifies if the domain in those checks aligns with the “From” domain.</li><li>Based on your DMARC policy (<code>p=</code>), it either delivers, quarantines, or rejects the message.</li></ol>Policy Options<ul><li><code>p=none</code>: Monitor only (no enforcement)</li><li><code>p=quarantine</code>: Mark suspicious emails as spam</li><li><code>p=reject</code>: Block unauthorized emails entirely</li></ul>Best Practices for DMARC<ul><li>Start with <code>p=none</code> to collect reports.</li><li>Review your DMARC reports for legitimate senders.</li><li>Move to <code>quarantine</code> and finally <code>reject</code> once everything is aligned.</li></ul><h2>How SPF, DKIM, and DMARC Work Together</h2>Think of SPF, DKIM, and DMARC as three layers of email defense.Layer Purpose Protects Against SPF Authorizes sending IP addresses Spoofing and unauthorized senders DKIM Signs messages to verify integrity Message tampering DMARC Enforces policy and alignment Phishing and domain abuseHere’s how the process works when you send an email:<ol><li>The recipient’s server checks if the sending IP is authorized by SPF.</li><li>It verifies the DKIM signature to ensure the message is intact.</li><li>It applies your DMARC policy to decide what to do with emails that fail either check.</li></ol>If both SPF and DKIM align with your domain and pass validation, your message is considered legitimate.<h2>How to Set Them Up for Your Domain</h2>Setting up these records takes just a few minutes but has long-term benefits.<h3>Step 1: Add SPF Record</h3>In your DNS settings, add a TXT record:<pre><code>v=spf1 include:autosend.com -all
</code></pre><h3>Step 2: Add DKIM Record</h3>Your email service provider (like AutoSend) gives you a DKIM key. Add it as:<pre><code>default._domainkey.yourdomain.com IN TXT "v=DKIM1; k=rsa; p=MIIBIjANBgkq..."
</code></pre><h3>Step 3: Add DMARC Record</h3>Finally, publish your DMARC policy:<pre><code>_dmarc.yourdomain.com IN TXT "v=DMARC1; p=quarantine; rua=mailto:dmarc@yourdomain.com; aspf=s; adkim=s"
</code></pre>Once added, use tools like:<ul><li><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://mxtoolbox.com/">MXToolbox</a></li><li><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://www.dmarcanalyzer.com/">DMARC Analyzer</a></li><li><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://www.mail-tester.com/">Mail-Tester</a></li></ul>to confirm that everything is working.<h2>Why This Matters for Deliverability</h2>Mailbox providers like Gmail and Yahoo use these checks to decide whether to trust your domain. Without them, even legitimate emails can end up in spam. Strong authentication helps build domain reputation, leading to better inbox placement and fewer delivery issues.Once SPF, DKIM, and DMARC are properly configured, you can take authentication a step further with <a target="_new" rel="noopener" class="break-all link-break text-gray-500 hover:underline decorated-link" href="https://autosend.com/blog/how-to-get-a-verified-checkmark-in-gmail-with-bimi">BIMI (Brand Indicators for Message Identification)</a>. BIMI allows you to display your verified logo and checkmark next to your emails in supported inboxes, signaling authenticity and boosting brand trust.<hr><h2>TL;DR</h2>To protect your domain and ensure your emails reach the inbox:<ol><li>Set up SPF to authorize your sending IPs.</li><li>Enable DKIM to sign and verify message integrity.</li><li>Enforce DMARC to align and control authentication results.</li></ol>Together, these three protocols secure your brand, prevent abuse, and improve deliverability.

If your legitimate emails are landing in spam or being spoofed by attackers, your authentication setup might be the problem. To make sure your emails are trusted, you need three essential protocols: SPF, DKIM, and DMARC.These technologies form the foundation of secure email delivery. Together, they prevent phishing, domain impersonation, and spam, ensuring that your messages reach the inbox safely.This guide explains what each protocol does, how they work together, and how to set them up correctly.Why Email Authentication MattersEvery day, millions of phishing emails are sent pretending to be from legitimate companies. Without proper authentication, spammers can forge your domain name and send fake messages that look real.Strong email authentication:Protects your brand reputationImproves deliverabilityIncreases user trustPrevents unauthorized senders from using your domainWhat Is SPF?SPF (Sender Policy Framework) is a DNS record that specifies which mail servers are allowed to send emails on behalf of your domain.When an email is received, the receiving mail server checks the sender’s domain and verifies if the sending IP address is listed in the SPF record.If it matches, the SPF check passes. If not, it fails and may be marked as spam or rejected.Example SPF Recordv=spf1 include:autosend.com -all
How it works:The receiving mail server extracts the domain from the “Return-Path” header.It looks up the SPF record for that domain.If the IP address sending the message matches one listed, the email is authenticated.Best Practices for SPFUse -all instead of ~all to enforce strict validation.Keep the record under 10 DNS lookups to avoid breaking SPF.Update it whenever you add or remove an email service.What Is DKIM?DKIM (DomainKeys Identified Mail) adds a digital signature to your emails to prove that the content has not been modified.Each outgoing email is signed with a private key that only your mail server knows.The recipient can then verify this signature using a public key stored in your domain’s DNS.Example DKIM Recordv=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0B...
How it works:Your mail server generates a DKIM signature and attaches it to each email header.The receiving server fetches the public key from your DNS.It verifies the signature to ensure that the email body and headers were not altered.Best Practices for DKIMUse at least a 2048-bit key for stronger security.Rotate DKIM keys periodically (every 6–12 months).Ensure your “From” domain matches the signing domain for alignment with DMARC.What Is DMARC?DMARC (Domain-based Message Authentication, Reporting, and Conformance) ties SPF and DKIM together and defines what to do when an email fails authentication.DMARC allows you to tell receiving servers how to handle unauthenticated messages (none, quarantine, or reject) and provides detailed reports on who is sending emails using your domain.Example DMARC Recordv=DMARC1; p=quarantine; rua=mailto:dmarc-reports@yourdomain.com; adkim=s; aspf=s
How it works:The receiving server checks if the email passes SPF or DKIM.It verifies if the domain in those checks aligns with the “From” domain.Based on your DMARC policy (p=), it either delivers, quarantines, or rejects the message.Policy Optionsp=none: Monitor only (no enforcement)p=quarantine: Mark suspicious emails as spamp=reject: Block unauthorized emails entirelyBest Practices for DMARCStart with p=none to collect reports.Review your DMARC reports for legitimate senders.Move to quarantine and finally reject once everything is aligned.How SPF, DKIM, and DMARC Work TogetherThink of SPF, DKIM, and DMARC as three layers of email defense.Layer Purpose Protects Against SPF Authorizes sending IP addresses Spoofing and unauthorized senders DKIM Signs messages to verify integrity Message tampering DMARC Enforces policy and alignment Phishing and domain abuseHere’s how the process works when you send an email:The recipient’s server checks if the sending IP is authorized by SPF.It verifies the DKIM signature to ensure the message is intact.It applies your DMARC policy to decide what to do with emails that fail either check.If both SPF and DKIM align with your domain and pass validation, your message is considered legitimate.How to Set Them Up for Your DomainSetting up these records takes just a few minutes but has long-term benefits.Step 1: Add SPF RecordIn your DNS settings, add a TXT record:v=spf1 include:autosend.com -all
Step 2: Add DKIM RecordYour email service provider (like AutoSend) gives you a DKIM key.Add it as:default._domainkey.yourdomain.com IN TXT "v=DKIM1; k=rsa; p=MIIBIjANBgkq..."
Step 3: Add DMARC RecordFinally, publish your DMARC policy:_dmarc.yourdomain.com IN TXT "v=DMARC1; p=quarantine; rua=mailto:dmarc@yourdomain.com; aspf=s; adkim=s"
Once added, use tools like:MXToolboxDMARC AnalyzerMail-Testerto confirm that everything is working.Why This Matters for DeliverabilityMailbox providers like Gmail and Yahoo use these checks to decide whether to trust your domain.Without them, even legitimate emails can end up in spam.Strong authentication helps build domain reputation, leading to better inbox placement and fewer delivery issues.Once SPF, DKIM, and DMARC are properly configured, you can take authentication a step further with BIMI (Brand Indicators for Message Identification).BIMI allows you to display your verified logo and checkmark next to your emails in supported inboxes, signaling authenticity and boosting brand trust.TL;DRTo protect your domain and ensure your emails reach the inbox:Set up SPF to authorize your sending IPs.Enable DKIM to sign and verify message integrity.Enforce DMARC to align and control authentication results.Together, these three protocols secure your brand, prevent abuse, and improve deliverability.

The email blog

Stories, strategies, and insights for sending better emails.