:id-selector
selector or pseudo-class · 17 supported, 2 partial, 1 unsupported across 21 clients
17 of 21 email clients render :id-selector fully (Sep 2, 2026 data); it breaks outright in Proton Mail.
- 6/7 webmail, 5/6 desktop, 6/8 mobile clients support :id-selector fully.
- Unsupported in Proton Mail.
- Partial in Gmail Android, Gmail iOS, behavior differs from browsers, test before relying on it.
- 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 Oct 13, 2019, synced by Emailens Sep 2, 2026.
Client Support
| Client | Category | Engine | Support |
|---|---|---|---|
| Gmail | webmail | Gmail Web | Supported |
| Gmail Android | mobile | Gmail Mobile | PartialSee caveat 1 |
| Gmail iOS | mobile | Gmail Mobile | PartialSee caveat 1 |
| Outlook 365 | webmail | Outlook Web | Supported |
| Outlook (New) | desktop | Outlook Web | Supported |
| Outlook Classic | desktop | Microsoft Word | Supported |
| Outlook iOS | mobile | Outlook Mobile | Supported |
| Outlook Android | mobile | Outlook Mobile | Supported |
| 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 | Supported |
| Yahoo Mail iOS | mobile | Yahoo | Supported |
| Samsung Mail | mobile | Samsung | Supported |
| Thunderbird | desktop | Gecko | Supported |
| HEY Mail | webmail | WebKit | Supported |
| Proton Mail | webmail | Proton | Unsupported |
| AOL Mail | webmail | AOL | Supported |
| Fastmail | webmail | Fastmail | Supported |
| Superhuman | desktop | Blink | Unknown |
Documented caveats (1)
- 1.Gmail Android, Gmail iOS: Partial. Not supported with non Google accounts.
Caveats recorded by caniemail.com (MIT) and carried verbatim, one entry per wording rather than per client.
Client-by-client behaviour for :id-selector
Fully supports :id-selector (17): Gmail, Outlook 365, Outlook (New), Outlook Classic, Outlook iOS, Outlook Android, Outlook for Mac, Apple Mail, Apple Mail iOS, Yahoo Mail, Yahoo Mail Android, Yahoo Mail iOS, Samsung Mail, Thunderbird, HEY Mail, AOL Mail, Fastmail.
Partial support (2): Gmail Android, Gmail iOS. Expect rendering quirks unique to each engine. Partial support typically means a subset of values, an ignored shorthand, or sanitizer-specific rewrites.
No support (1): Proton Mail. Plan fallbacks for these clients before relying on :id-selector in production sends.
Behaviour unverified in: Superhuman.
Fixes & Workarounds
Proton Mail
Unsupported":id-selector" is not supported in this email client.
Gmail Android
Partial":id-selector" is not supported in this email client.
Gmail iOS
Partial":id-selector" is not supported in this email client.
Related Features
Check your own HTML for :id-selector
Paste your own, or run the sample below. Analyzed in this page, with no signup and nothing stored.
Test your :id-selector layout across 21 email clients
Preview rendering, catch CSS issues, and see how :id-selector 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 Oct 13, 2019 as the last time :id-selector was tested in a real client, 6 years before this sync. Syncing copies that result forward, it does not re-test it. Carried in @emailens/engine data v0.12.2.