The marketing team had spent weeks on the campaign. Perfect copy, beautiful design, carefully segmented audience. They scheduled it for Tuesday at 10 AM—optimal send time according to their data. Tuesday morning arrived, they hit send, and 50,000 emails went out.
With a broken unsubscribe link.
The link pointed to a staging URL that returned a 404. Complaints flooded in. Their ESP flagged the account. What should have been their best campaign became a deliverability crisis that took months to recover from.
A pre-send checklist would have caught this in thirty seconds.
Before every send
Links work. Click every link in your email. Not just the main CTA—every link, including the unsubscribe link, social icons, and footer links. Verify they go where they should and don't redirect through broken tracking URLs.
Personalization renders correctly. If your email uses merge tags ({{first_name}}, {{company}}, etc.), verify they render with actual data. Check what happens when data is missing—does it show a sensible fallback or an ugly {{first_name}}?
Subject line is correct. Read it out loud. Check for typos. Verify it matches the email content. Confirm it's not truncated awkwardly on mobile (keep it under 50 characters for safety).
From name and address are correct. Verify the From name is what recipients expect. Confirm the From address is correct and can receive replies (if replies are expected). Check that the reply-to address is set correctly if different from the From address.
Preheader text is set. The preheader (preview text) appears after the subject line in most email clients. If you don't set it explicitly, email clients pull the first text from your email—often "View in browser" or other boilerplate. Set it intentionally.
Content verification
Images load. View the email with images enabled and disabled. Verify all images load from the correct URLs. Check that alt text is present and meaningful for when images don't load.
Mobile rendering is acceptable. Preview on actual mobile devices or use a preview tool. Text should be readable without zooming. Buttons should be large enough to tap. The layout should adapt sensibly to narrow screens.
Dark mode doesn't break the design. Many email clients now have dark mode. Preview your email in dark mode to catch inverted colors, invisible text, or broken layouts. Design with dark mode in mind from the start.
Plain text version exists and is readable. If you're sending HTML email, include a plain text alternative. Some recipients prefer it, and some spam filters penalize HTML-only emails. The plain text version should be readable, not just a dump of the HTML content.
Legal requirements are met. Commercial emails need a physical address and unsubscribe mechanism. Transactional emails have different requirements but still need sender identification. Know which regulations apply to your email and verify compliance.
Technical verification
Test email received successfully. Send a test to yourself and at least one other person. Verify it arrives, renders correctly, and doesn't land in spam. If possible, test across multiple email clients (Gmail, Outlook, Apple Mail at minimum).
Authentication passes. Check the headers of your test email to verify SPF, DKIM, and DMARC pass. If authentication fails on test emails, it will fail on production emails. Fix authentication issues before sending.
Tracking is working. If you're tracking opens and clicks, verify the tracking pixels and link wrapping are functioning. Send a test, open it, click links, and confirm the events appear in your analytics.
Segmentation is correct. Double-check your recipient list or segment. Verify the count matches expectations. Spot-check a few recipients to confirm they should receive this email. Sending to the wrong segment is embarrassing at best, compliance-violating at worst.
Scheduling is correct. If scheduling for later, verify the date, time, and timezone. A campaign scheduled for 10 AM in the wrong timezone reaches people at 3 AM. Confirm the scheduled time is when you intend.
The final check
Read the email as a recipient would. Step back from the details and read the email fresh. Does it make sense? Is the call-to-action clear? Would you click through? Would you unsubscribe?
Have someone else review it. Fresh eyes catch what you've become blind to. A quick review by a colleague catches typos, confusing phrasing, and obvious errors that you've looked at too many times to see.
Confirm you're ready for responses. If the email invites replies, is someone monitoring the inbox? If it drives traffic to a landing page, is the page ready? If it promotes a limited offer, is inventory sufficient? The email is just the start of the interaction.
Building the habit
Checklists only work if you use them. Build the pre-send check into your workflow so it's automatic, not optional.
Create a literal checklist—a document or tool that you go through before every send. The act of checking boxes forces attention to each item. Skipping steps becomes conscious rather than accidental.
For teams, make the checklist part of the approval process. No email goes out without documented completion of the pre-send checks. This catches individual oversights and creates accountability.
Automate what you can. Some checks (link validation, authentication verification, mobile preview) can be automated with tools. Automated checks are consistent; human checks are fallible.
When something goes wrong despite the checklist, add a check for it. Checklists evolve based on experience. The broken unsubscribe link? That's now a specific checklist item, not just "links work."
When to skip the checklist
Never.
The email that seems too simple to need checking is the one that goes out with a typo in the subject line. The urgent send that can't wait for verification is the one that goes to the wrong segment. The routine newsletter that's "the same as always" is the one where the date is wrong.
The checklist takes five minutes. The recovery from a preventable mistake takes days, weeks, or months. The math is simple.
Frequently asked questions
How long should pre-send verification take?
For a simple email, 5-10 minutes. For complex campaigns with multiple segments, personalization, and integrations, 30 minutes or more. The time investment is trivial compared to the cost of mistakes.
Should I send test emails to real addresses or use testing tools?
Both. Testing tools (Litmus, Email on Acid) show rendering across clients. Real test emails verify actual delivery, authentication, and tracking. They catch different problems.
What if I find a problem right before a scheduled send?
Delay the send. A late email is better than a broken email. If the timing is truly critical (event reminder, time-sensitive offer), fix what you can and document what you couldn't. But usually, the timing isn't as critical as it feels in the moment.
How do I verify segmentation is correct?
Check the recipient count against expectations. Export a sample and spot-check individual recipients. If your ESP supports it, preview the email as specific recipients to verify personalization. For critical sends, have someone else independently verify the segment criteria.