Free Email HTML Code Analyzer
Email Coding Best Practices
- Use tables for layout instead of div-based layouts
- Maximum width of 600-800px for best readability
- Use nested tables instead of complex CSS positioning
- Add cellpadding and cellspacing attributes to tables
- Always include alt text for images
- Specify width and height attributes
- Keep image file sizes under 1MB
- Use absolute URLs for all images
- Use web-safe fonts or include fallbacks
- Minimum font size of 14px for body text
- Use HTML entities for special characters
- Specify line-height for better readability
- Use HTML4/XHTML1 doctype for maximum compatibility
- Include inline CSS instead of style blocks
- Use six-character hex codes for colors
- Add role="presentation" to layout tables
Free Email HTML Code Analyzer
Our free email HTML code analyzer checks your email template for compatibility issues with Gmail, Outlook, Apple Mail, and Yahoo Mail. Paste your HTML and get a detailed report of unsupported tags, problematic CSS properties, and accessibility warnings — all in one place.
Email HTML is notoriously inconsistent across clients. CSS that works perfectly in a browser may be completely ignored by Outlook. Tags that render fine in Gmail may break in Yahoo Mail. Without testing, you risk sending campaigns that look broken to a significant portion of your audience.
This tool is designed for email developers, designers, and marketers who build HTML email templates. It surfaces the most common compatibility issues and provides actionable recommendations for fixing them, saving hours of manual testing across multiple email clients.
How to Use This Tool
- Paste your HTML email code into the text area on the left.
- Click Analyze Code.
- Review the results for each email client — red badges indicate errors, yellow indicate warnings.
- Expand each client section to see specific issues and recommendations.
- Fix the issues and re-analyze until all critical errors are resolved.
Frequently Asked Questions
Which email clients does this tool check?
The analyzer checks compatibility with Gmail, Outlook, Apple Mail, and Yahoo Mail — the four most widely used email clients globally.
What CSS properties are not supported in Outlook?
Outlook has limited CSS support. It does not support border-radius, box-shadow, display:flex, display:grid, background-size, and many other modern CSS properties. Use table-based layouts for maximum Outlook compatibility.
Can I export the analysis report?
Yes. After analyzing your code, click Export as HTML to generate a standalone report you can save or share with your team.