Avoid These 5 Mistakes While Sending Transactional Emails

Transactional emails are the quiet workhorses of any product. They confirm signups, reset passwords, send receipts, and quietly keep users connected to what they just did.

But here’s the catch. Because they “just work,” most teams stop paying attention to them after setting things up. That’s when small mistakes start slipping in. A missing link. A message stuck in spam folder. Or emails that never arrive.

These little things can hurt your product’s trust, conversions, and reputation more than you think.

Let’s talk about the five common mistakes people make with transactional emails and how to avoid them.

1. Mixing transactional and marketing emails

This is one of the biggest red flags!

Transactional emails are triggered by what the user does, like signing up, verifying their address, or completing a payment. Marketing emails, on the other hand, are sent by you, such as newsletters, offers, or feature updates.

When you mix the two, you create confusion and risk deliverability issues. Even a single promotional line can change how email providers treat your message.

Example of what not to do:

“Your password has been reset successfully. By the way, here’s 20% off your next order.”

That’s not transactional anymore. It’s a marketing email disguised as a notification. Email clients (Gmail, Outlook, etc) most probably blacklist your sending domain for doing this!

If you send both kinds, separate them properly. Use subdomains like notifications.yourdomain.com for transactional emails and updates.yourdomain.com for marketing. It helps you stay compliant and keeps your sender reputation clean.

Tip: We use main (root) domain for certain marketing emails like product updates because they need to come from a builder than a brand. We also encourage users to reply to these emails by asking for feedback or feature requests.

2. Skipping authentication and deliverability setup

Email authentication is not optional. Without it, your messages might never reach inboxes.

Set up SPF, DKIM, and DMARC for your sending domain. These records prove that your emails are legitimate and authorized. Without them, providers like Gmail or Outlook might flag them as suspicious.

Think of these as ID checks for your emails. No ID, no entry.

It’s good practice to run a deliverability test every few months using tools like Mail-Tester or DMARC checkers. It keeps your transactional emails reliable and builds trust with both users and email providers.

3. Forgetting to handle delivery failures and retries properly

Even the best email infrastructure can fail sometimes. Servers can timeout, domains can throttle requests, or recipients’ mailboxes can temporarily reject messages.

If your app isn’t set up to handle retries or log failures, some of your most important messages might never get delivered.

Imagine a user waiting for a password reset link that failed to send because of a temporary network issue. They’ll just assume your product is broken.

To avoid this, implement a retry mechanism with exponential backoff and store failed events in a queue or log for review. Most modern email APIs provide webhooks or event logs for this exact reason.

It’s not enough to “fire and forget.” Always know what happened after you clicked send.

4. Making them hard to read or inaccessible

A lot of transactional emails fail because of how they’re written.

People open these emails when they’re trying to complete a specific task such as verifying an account, resetting a password, or viewing a receipt. They’re not in the mood to read long paragraphs.

Make it easy.

• Keep sentences short and direct.

• Use descriptive subject lines like “Confirm your email” or “Your order is confirmed.”

• Place the main action or link at the top.

• Add alt text to images and maintain good contrast for readability.

Accessibility is not just a compliance requirement. It’s how you show respect for your users’ time and attention.

5. Not tracking logs or monitoring performance

Transactional emails are often treated as “set it and forget it.”

But things break. DNS updates, expired credentials, or throttling by mail servers can stop your messages from reaching users. If you don’t monitor delivery logs, bounce rates, or error messages, you won’t know there’s a problem until users start complaining.

Regularly reviewing logs helps you catch issues early. You can also identify trends like delayed deliveries or domain-specific bounce patterns. Treat this like uptime monitoring for your email system.

Bonus: Don’t add an unsubscribe link to transactional emails

This might sound strange, but you should not include an unsubscribe link in your transactional emails.

These emails are often critical to account security and compliance. Think password resets, account verifications, billing alerts, or privacy notifications. If users could unsubscribe from these, they might miss important system information that affects their accounts.

However, this applies only to genuine transactional emails. If your message includes any promotional content such as product updates, feature highlights, or discounts, it becomes a marketing email, and laws like CAN-SPAM or GDPR require a clear opt-out link.

The best rule of thumb is:

• Keep transactional emails strictly functional.

• Reserve unsubscribe links for marketing or promotional messages.

That balance keeps you compliant while ensuring essential messages always reach your users.

Transactional emails might look simple, but they carry real weight. They’re often the most opened messages your users will ever receive.

Avoid these five mistakes: mixing content types, skipping authentication, not handling delivery failures, writing unclear copy, and neglecting logs. And remember, not every email needs an unsubscribe link.

When your transactional emails are fast, clear, and consistent, they quietly strengthen your brand every single day.