How many email clients support transform?

It works in 7 of 21, partial in 1, not supported in 13.

Does transform work in Fastmail?

transform works in Fastmail. Closest to HEY Mail: Fastmail, which agrees on 173 of the 235 features both are tested on.

transform in HEY Mail

Works transform works in HEY Mail.

Works in 7 of 21 · partial in 1 · not supported in 13

Which clients

Works: Apple Mail, Apple Mail iOS, Samsung Mail, Thunderbird, HEY Mail, Proton Mail, Fastmail
Partial: Superhuman
Not supported: Gmail, Gmail Android, Gmail iOS, Outlook 365, Outlook (New), Outlook Classic, Outlook iOS, Outlook Android, Outlook for Mac, Yahoo Mail, Yahoo Mail Android, Yahoo Mail iOS, AOL Mail

The fix for the clients that need it

Needed in 14 of 21: Gmail, Gmail Android, Gmail iOS and 11 more.

Pre-render transformed states as images or use table layout

instead

4 lines

<!-- Pre-render rotated content as an image -->
<img src="rotated-content.png" width="200" height="200"
  alt="Rotated content"
  style="display: block; border: 0;" />

Show the original

before

3 lines

<div style="transform: rotate(45deg);">
  Rotated content
</div>

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Every feature in HEY Mail · transform in every client

Questions

How many email clients support transform?: It works in 7 of 21, partial in 1, not supported in 13.
Does transform work in Fastmail?: transform works in Fastmail. Closest to HEY Mail: Fastmail, which agrees on 173 of the 235 features both are tested on.

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caniemail (MIT) via @emailens/engine 0.18.22 · tested upstream 28 Feb 2019 · data last changed 10 Nov 2026 · Outlook (New) cells are the engine's mapping