Structural issue
Fix width, tables, wrapping, and reading order first, then resend the complete email. Don’t use screenshots instead of real validation.
HTML email checklist
Validate 24 HTML email checks before launch
Don’t rely on a single design mockup. Check headers and sender identity first, then cover layout, interactions, accessibility, and real delivery in a separate inbox.
Release notes
When you find an issue, record the evidence before editing the template
Record the client, screen width, send time, subject, and issue location in the same checklist item. This helps distinguish template errors, delivery delays, and client compatibility problems.
Content issue
Check empty variables, time zones, language, verification codes, and action links, and update the plain-text version at the same time.
Delivery issue
Record the request time and provider status. Avoid repeated sends that can hide queueing, rate limits, or an incorrectly entered address.
Final pass
After the checklist passes, send a real email for final QA
Copy the independent address, trigger the template from the actual sending system, then review the headers, HTML body, and mobile rendering in the inbox.
Open test inbox