@keyframes
CSS at-rule · 8 supported, 1 partial, 12 unsupported across 21 clients
8 of 21 email clients render @keyframes fully (Sep 2, 2026 data); it breaks outright in Gmail, Gmail Android, Gmail iOS and 9 more.
- 3/7 webmail, 3/6 desktop, 2/8 mobile clients support @keyframes fully.
- Unsupported in Gmail, Gmail Android, Gmail iOS, Outlook 365 and 8 more.
- Partial in Superhuman, behavior differs from browsers, test before relying on it.
- Outlook Classic (Word engine, supported to at least 2029) does not fully support @keyframes, and its replacement changes little here; see the deprecation diff.
- Across all clients, only 6 of 298 tracked HTML/CSS features render identically everywhere.
Source: caniemail.com (MIT), via the Emailens engine. Last tested upstream May 25, 2021, synced by Emailens Sep 2, 2026.
Client Support
| Client | Category | Engine | Support |
|---|---|---|---|
| Gmail | webmail | Gmail Web | Unsupported |
| Gmail Android | mobile | Gmail Mobile | Unsupported |
| Gmail iOS | mobile | Gmail Mobile | Unsupported |
| Outlook 365 | webmail | Outlook Web | Unsupported |
| Outlook (New) | desktop | Outlook Web | Unsupported |
| Outlook Classic | desktop | Microsoft Word | Unsupported |
| Outlook iOS | mobile | Outlook Mobile | Unsupported |
| Outlook Android | mobile | Outlook Mobile | Unsupported |
| Outlook for Mac | desktop | WebKit | Supported |
| Apple Mail | desktop | WebKit | Supported |
| Apple Mail iOS | mobile | WebKit | Supported |
| Yahoo Mail | webmail | Yahoo | Supported |
| Yahoo Mail Android | mobile | Yahoo | Unsupported |
| Yahoo Mail iOS | mobile | Yahoo | Unsupported |
| Samsung Mail | mobile | Samsung | Supported |
| Thunderbird | desktop | Gecko | Supported |
| HEY Mail | webmail | WebKit | Supported |
| Proton Mail | webmail | Proton | Unsupported |
| AOL Mail | webmail | AOL | Unsupported |
| Fastmail | webmail | Fastmail | Supported |
| Superhuman | desktop | Blink | Partial |
Client-by-client behaviour for @keyframes
Fully supports @keyframes (8): Outlook for Mac, Apple Mail, Apple Mail iOS, Yahoo Mail, Samsung Mail, Thunderbird, HEY Mail, Fastmail.
Partial support (1): Superhuman. Expect rendering quirks unique to each engine. Partial support typically means a subset of values, an ignored shorthand, or sanitizer-specific rewrites.
No support (12): Gmail, Gmail Android, Gmail iOS, Outlook 365, Outlook (New), Outlook Classic, Outlook iOS, Outlook Android, Yahoo Mail Android, Yahoo Mail iOS, Proton Mail, AOL Mail. Plan fallbacks for these clients before relying on @keyframes in production sends.
Fixes & Workarounds
Gmail
Unsupported`@keyframes` is not supported in this email client.
Gmail Android
Unsupported`@keyframes` is not supported in this email client.
Gmail iOS
Unsupported`@keyframes` is not supported in this email client.
Outlook 365
Unsupported`@keyframes` is not supported in this email client.
Outlook (New)
Unsupported`@keyframes` is not supported in this email client.
Outlook Classic
Unsupported`@keyframes` is not supported in this email client.
Outlook iOS
Unsupported`@keyframes` is not supported in this email client.
Outlook Android
Unsupported`@keyframes` is not supported in this email client.
Yahoo Mail Android
Unsupported`@keyframes` is not supported in this email client.
Yahoo Mail iOS
Unsupported`@keyframes` is not supported in this email client.
Proton Mail
Unsupported`@keyframes` is not supported in this email client.
AOL Mail
Unsupported`@keyframes` is not supported in this email client.
Superhuman
Partial`@keyframes` is not supported in this email client.
Related Features
Check your own HTML for @keyframes
Paste your own, or run the sample below. Analyzed in this page, with no signup and nothing stored.
Test your @keyframes layout across 21 email clients
Preview rendering, catch CSS issues, and see how @keyframes displays across Outlook, Gmail, and Apple Mail. Free, no account needed.
Instant live preview · No signup required · 21 email engines
Last tested upstream: · Last synced by Emailens:
caniemail.com (MIT) records May 25, 2021 as the last time @keyframes was tested in a real client, 5 years before this sync. Syncing copies that result forward, it does not re-test it. Carried in @emailens/engine data v0.12.2.