See your newsletter before it goes out.
Paste HTML and check how the email looks on desktop, mobile and in dark mode. The check finds what Gmail clips, Outlook distorts or spam filters dislike.
The way you built the HTML.
Paste HTML or load the example and the preview appears here.
Check
Paste HTML or load the example and the preview appears here.
Runs in your browser, the HTML never leaves your computer. Your browser loads images from their servers, just as when opening the email.
How it works
Paste, switch, tick off.
- 01
Paste HTML
Copy the source from your email tool, load an .html file or use the example.
- 02
Switch the view
Desktop at 680 px, phone at 375 px, plus light, dark and inverted like some mail apps.
- 03
Work through the check
Errors on top, notes below. Every item says in one sentence why it matters.
Frequently asked questions
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Spam Checker
Paste subject line and HTML, get a spam score: which words, links and elements make filters suspicious and what to change.
And what are your competitors sending?
Reyo reads your competitors’ newsletters, push notifications, Meta ads and websites and tells you what to do about them.