Email signature HTML checker
Paste your email signature’s HTML. We check its size against Gmail’s limit and flag what breaks in Outlook and Gmail, with a fix for each problem.
Size0 / 10,000
Results appear here as soon as you paste.
What we check
- Length against Gmail’s 10,000-character signature limit.
- <style> blocks, scripts, flexbox, grid and absolute positioning, which email clients strip or ignore.
- Images: absolute HTTPS addresses, no embedded base64, alt text and width attributes.
- Tags that are opened but never closed.
Your HTML is checked on our server and not stored. Or build a signature that passes every check in the free generator.