Settings5 min read•Audience: Developers, Designers
Export Settings & Minification
Configure HTML minification, comment stripping, and payload size optimization to prevent Gmail message clipping.
Key Takeaways
- Gmail automatically clips any email message whose HTML file size exceeds 102 KB, hiding content behind a "[Message clipped] View entire message" link.
- PostBrix offers integrated minification via html-minifier-terser to safely collapse whitespace and reduce payload sizes by up to 40%.
- Minification carefully preserves critical MSO conditional comments (<!--[if mso]>) required by Outlook.
The Gmail 102 KB Clipping Rule#
If your compiled HTML source code exceeds 102 KB (104,448 bytes):
- Gmail stops rendering your email at the 102 KB boundary.
- A button labeled "[Message clipped] View entire message" appears at the bottom.
- Critical footer elements—including your CAN-SPAM postal address, unsubscribe link, and open tracking pixel—are cut off, harming deliverability and compliance.
Note: The 102 KB limit applies only to the raw HTML markup bytes, not external images or attachments.
How PostBrix Minification Works#
When you enable Minify HTML in export settings, the PostBrix engine runs html-minifier-terser with email-safe parameters:
- Collapses redundant whitespace and line breaks.
- Removes standard developer comments while strictly preserving Microsoft conditional comments (
<!--[if mso]>and<![endif]-->). - Keeps the final file size well below the 102 KB limit while maintaining 100% email client compatibility.
Frequently Asked Questions
Does minification break Outlook desktop rendering?
No. PostBrix minification specifically protects MSO conditional comments and preserves internal table padding structures required by Outlook.
How do I check the exact byte size of my email before sending?
The Export Modal displays the exact payload size in kilobytes (e.g., "58.4 KB / 102 KB limit") with a green status indicator.