Local content analysis
HTML Email Preflight Checker
Catch common HTML email, accessibility, link, and content problems before a controlled send. The analyzer uses the browser's parser and never uploads your draft.
A preflight is not a client matrix
Static analysis can identify scripts, forms, missing image alternatives, absent plain text, placeholder links, and layout signals. It cannot reproduce every Gmail, Outlook, Apple Mail, or assistive-technology rendering path.
Use email-safe foundations
Keep the primary layout simple, use presentation tables where needed, provide meaningful text and alt attributes, inline essential styles, and make actions understandable without images. A responsive viewport and mobile rules improve small-screen behavior.
Always send a controlled test
Render the final server-produced HTML with representative data, send it to inboxes you administer, inspect links and received headers, and test keyboard and screen-reader reading order before production.
Questions about this tool
Does this checker send an email?
No. It only analyzes the values in this page and makes no network request.
Does a clean result guarantee email-client compatibility?
No. It reduces common risks but cannot emulate all engines, settings, dark modes, security filters, or assistive technologies.
Can this validate an email address?
It checks only basic address syntax. It cannot establish that a mailbox exists or will accept mail.