About MailMode
MailMode was built to make email dark mode testing a little less painful.
MailMode started as a side project after spending far too long debugging emails that looked completely different once dark mode got involved.
If you build emails, you already know the routine: paste into one tool, test in another, send yourself a proof, open it in a few clients, spot something odd, then try to work out whether the problem is your CSS, the email client, or dark mode being dark mode.
The aim with MailMode is simple: make that first pass faster and clearer. Paste or upload an email, compare light and dark mode side by side, switch viewports, and get practical checks that point to the things worth reviewing.
It is not trying to replace full enterprise testing suites. It is intentionally lightweight: a focused tool for email developers, marketers and teams who need a quick, useful view before they move into final QA.
Practical previews and useful signals
Light & dark previews
Compare both modes side by side without setting up a full test workflow.
Dark mode previews
Check authored CSS, partial invert and full invert simulations so problems are easier to spot.
MJML support
Upload or paste MJML and preview the rendered email output.
React Email support
Preview static React Email templates through a safe renderer.
Shareable previews
Create temporary hosted preview links for quick review.
Health checks
Review accessibility, tracking, links, images and inbox preview basics.
Accessibility analysis
Catch common readability and accessibility risks before sending.
Viewport testing
Switch between mobile, standard email widths and desktop canvas views.
Built for real email workflows
Email development is already complicated enough. MailMode is designed to stay fast, focused and understandable.
Clear previews are more useful than an overwhelming dashboard. When something looks wrong, the tool should help you understand why, not bury the useful bit under noise.
Preview first. Panic less.Small, useful improvements
Have feedback or ideas?
MailMode is evolving quickly and feedback from real email developers genuinely helps shape the product.