Verified 2026-09-06
Email client compatibility, verified — not promised
Every signature generator claims to “work in Outlook”. This page shows how Sigmint proves it: all 23 templates are automatically rendered and checked against the constraints that actually break signatures in Outlook, Gmail and Apple Mail — on every single deploy. The matrix below is generated by running those checks, not written by hand.
✓ 23/23 templates pass all 6 checks as of 2026-09-06
The verification matrix
Each template is rendered with full sample data — logo, photo, banner, and hosted social icons — and its output is tested for each constraint.
| Template | Table-based layout | No <style> blocks | No CSS classes | Balanced table markup | Absolute https images | Explicit image dimensions |
|---|---|---|---|---|---|---|
| Classic | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Minimal | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Modern | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Compact | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Elegant | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Card | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Bold | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Corporate | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Stacked | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Hallmark | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Sidebar | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Header | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Vibrant | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Photohero | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Editorial | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Duotone | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Portfolio | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Badges | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Developer | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Refined | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Inset | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Tile | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Grid | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
Why each check matters
Table-based layout
Outlook desktop renders email with Microsoft Word’s engine, which ignores most CSS layout. Nested tables are the only structure that renders identically everywhere.
No <style> blocks
Outlook strips the <head> — and Gmail historically clipped or ignored embedded styles. Every style must live inline on the element itself.
No CSS classes
Class-based styling depends on a stylesheet surviving the mail client. Ours never does, because there is nothing external to lose.
Balanced table markup
An unclosed table or cell makes Outlook’s Word engine mis-nest the rest of the message.
Absolute https images
Relative image paths break the moment the HTML leaves your machine, and many clients block or strip http:// images.
Explicit image dimensions
Without fixed dimensions, Outlook renders images at natural size and reflows the layout while images load.
Frequently asked questions
Do email signatures made with Sigmint work in Outlook?
Yes. Every template is generated as nested-table HTML with inline styles and no <style> blocks — the constraints Outlook’s Word rendering engine imposes — and every template is automatically re-checked against those constraints on every deploy. The verification matrix on this page is produced by running those checks, not written by hand.
Why do email signatures break in Outlook?
Outlook for Windows renders HTML with Microsoft Word’s engine, not a browser engine. It ignores most CSS layout (flexbox, grid, floats), strips <style> blocks in the <head>, and mishandles margins and backgrounds. Signatures built with modern web CSS therefore collapse; only nested tables with inline styles render reliably.
How is this compatibility report verified?
The matrix is computed at build time by rendering all 22 templates with full sample data (logo, photo, banner, social icons) and testing the output for each structural constraint. The same checks run in CI on every commit, so a regression fails the build before it can ship.
Do the signatures work in Gmail and Apple Mail too?
Yes — the same table-based, inline-styled HTML that survives Outlook also renders correctly in Gmail (which limits embedded CSS support) and Apple Mail (which is the most standards-friendly of the three). Building for the strictest client makes the others follow.
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