Email Newsletter Compatibility Checker

Paste your newsletter's web markup or upload an HTML file to check compatibility across email clients

Paste HTML source

Or upload a .html file

Advanced options

How do most readers open your emails? A mix, no strong preference Mostly on desktop Mostly on mobile

Issues that only show up on the other device get downgraded a severity level. Pick "Mostly on mobile" and responsive-layout issues (media queries, srcset, aspect-ratio) get bumped up to critical instead, since mobile readers feel a broken layout the most.

Result file format

Result content Critical Minor Informative

Findings