Free HTML email validator
Validate your HTML email code for cross-client compatibility. Catch issues in Outlook, Gmail, Apple Mail, and more before you hit send.
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How the HTML email validator works
1
Paste your HTML
Copy your email template HTML and paste it into the editor above. We accept any HTML email code.
2
Instant validation
Our validator checks 30+ rules across 8 categories — structure, layout, Outlook compatibility, dark mode, and more.
3
Fix & improve
Review the issues sorted by severity, apply the fixes, and re-validate until your score is in the green.
Frequently Asked Questions
FAQs about HTML email validation
Email Builder
Build emails that render perfectly everywhere
MailGreet's drag-and-drop email builder generates cross-client compatible HTML automatically — no manual coding or validation needed.