01
Bring existing HTML
Use a signature created by a designer, generator, CMS, agency or your own code.
Email signature compatibility checker
Fix HTML email signatures before Outlook breaks them.
Paste existing signature HTML. SigLint finds risky markup and CSS, explains why it may break across Outlook, Gmail and other clients, and shows practical fixes.
AM
Alex Morgan
Marketing Manager
Outlook compatibilityCompatibility issues found
Free checker
Paste your signature HTML
Analysis happens in your browser. SigLint does not upload or store the HTML you paste here.
1. Signature HTML
No file selected
Static analysis only. SigLint does not emulate Outlook or Gmail rendering.
2. Findings
Your results will appear here.
Issues are grouped by severity and affected client.
Issues are grouped by severity and affected client.
How it works
A linter, not another signature generator
02
See evidence
Every finding explains the risky markup, affected client and recommended direction.
03
Fix deliberately
SigLint avoids pretending a browser preview is an authentic Outlook render.
Want to inspect the checker itself? Browse the Rules Library, read the methodology, or review material changes in the changelog.