Free email marketing tools for 2026. Email subject line checker with character-count-per-client, spam word detector, UTM builder for email campaigns, HTML email size checker with Gmail 102 KB clip warning, and WCAG contrast checker for accessible email design.
Standalone checks for the most common email marketing mistakes. Do the thing, see the answer, ship. No sign-up, no login, no saved state.
Subject Line Checker
Test your email subject line against every major inbox client. See truncation at Gmail mobile, Apple Mail, Outlook, Yahoo. Flag spam triggers. Free, no sign-up.
Spam Word Checker
Paste your email copy. Get a real-time list of spam trigger words that push messages into the Promotions tab or Spam folder. 120+ patterns covering subject, body, and CTA text.
UTM Builder
Build Google Analytics UTM URLs for your email campaigns. Set source, medium, campaign, content, and term. Copy the full URL or download a CSV of variants.
Email Size Checker
Paste your email HTML. Get the rendered size in KB, Gmail clip warning (102 KB limit), count of external images, and a breakdown of what's eating your budget.
Contrast Checker
Check WCAG contrast ratio between any text color and background color. AA (4.5:1) and AAA (7:1) thresholds. Specific to email where every inbox renders colors slightly differently.