Does Mailgun include a built-in CSS inliner?

Mailgun provides basic functionality but lacks granular control. Mailgun requires you to inline CSS yourself. Their templating engine does not auto-inline.

Is there a free way to CSS inlining for Mailgun campaigns?

Yes. The MiN8T CSS Inliner below runs entirely in your browser — no signup, no upload, and the output works with any Mailgun workflow.

What image size limit does Mailgun enforce?

Mailgun accepts uploads up to 5000 KB per image and recommends a max width of 600px for email body width. Supported formats: JPG, PNG, GIF, WebP.

Works with Mailgun

CSS Inliner for Mailgun: Free Browser-Based Tool

→ Open the free CSS Inliner

Browser-only, no signup, no upload. Output works with any Mailgun campaign.

Built by the MiN8T Engineering Team · Updated 28 May 2026

Mailgun's built-in tools cover the basics, but the CSS inliner workflow often benefits from a dedicated, browser-only preprocessor before uploading. Outlook desktop (Word rendering engine) ignores