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

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 Matters

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.

Before You Start: Technical Foundation

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 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 [email protected] and [email protected] 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 Timeline

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.

The Week-by-Week Warming Schedule

For Low Volume Senders (up to 5,000 emails/day)

1. 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.

2. Week 2: Increase to 200-500 emails per day. Maintain high engagement by sending relevant content.

3. 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.

4. 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)

1. Week 1: Send 200-500 emails per day to your most engaged segments.

2. Week 2: Increase to 1,000-2,000 emails per day.

3. Week 3: Jump to 5,000-10,000 emails per day.

4. Week 4: Reach 15,000-20,000 emails per day.

5. Week 5: Scale to 30,000-40,000 emails per day.

6. Week 6: Hit your target volume of 50,000 emails per day.

For High Volume Senders (50,000+ emails/day)

1. Week 1-2: Start with 500-1,000 emails per day, focusing exclusively on highly engaged contacts.

2. Week 3-4: Increase to 10,000-20,000 emails per day.

3. Week 5-6: Scale to 40,000-80,000 emails per day.

4. 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: Consistency

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.

Engagement is Your Best Friend

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.

Segmentation Strategy During Warming

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:

• Weeks 1-2: Only Tier 1

• Weeks 3-4: Tier 1 + Tier 2

• Weeks 5-6: Tier 1 + Tier 2 + Tier 3

• Week 7+: All tiers, but consider a reactivation campaign for Tier 4

Transactional vs. Marketing Email Warming

The 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 Progress

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. AutoSend shows all of this in your dashboard, including detailed activity tracking and webhook events for bounces and complaints.

Tools for Testing and Monitoring

Mail-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 Avoid

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.

Special Scenarios

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.

After Warming: Maintaining Your Reputation

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.

Starting Your Warming Process

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.