text-decoration-line
CSS property · 16 supported, 0 partial, 2 unsupported across 21 clients
16 of 21 email clients render text-decoration-line fully (Oct 14, 2026 data); it breaks outright in Outlook Classic, AOL Mail.
- 4/7 webmail, 4/6 desktop, 8/8 mobile clients support text-decoration-line fully.
- Unsupported in Outlook Classic, AOL Mail.
- Outlook Classic (Word engine, supported to at least 2029) does not fully support text-decoration-line, one of the few features its replacement actually fixes; 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 Dec 6, 2023, synced by Emailens Oct 14, 2026.
Client Support
| Client | Category | Engine | Support |
|---|---|---|---|
| Gmail | webmail | Gmail Web | Supported |
| Gmail Android | mobile | Gmail Mobile | Supported |
| Gmail iOS | mobile | Gmail Mobile | Supported |
| Outlook 365 | webmail | Outlook Web | Supported |
| Outlook (New) | desktop | Outlook Web | Supported |
| Outlook Classic | desktop | Microsoft Word | Unsupported |
| 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 | Unknown |
| Proton Mail | webmail | Proton | Supported |
| AOL Mail | webmail | AOL | Unsupported |
| Fastmail | webmail | Fastmail | Unknown |
| Superhuman | desktop | Blink | Unknown |
Client-by-client behaviour for text-decoration-line
Fully supports text-decoration-line (16): Gmail, Gmail Android, Gmail iOS, Outlook 365, Outlook (New), Outlook iOS, Outlook Android, Outlook for Mac, Apple Mail, Apple Mail iOS, Yahoo Mail, Yahoo Mail Android, Yahoo Mail iOS, Samsung Mail, Thunderbird, Proton Mail.
No support (2): Outlook Classic, AOL Mail. Plan fallbacks for these clients before relying on text-decoration-line in production sends.
Behaviour unverified in: HEY Mail, Fastmail, Superhuman.
Fixes & Workarounds
Outlook Classic
Unsupported"text-decoration-line" is not supported in this email client.
AOL Mail
Unsupported"text-decoration-line" is not supported in this email client.
Related Features
Check your own HTML for text-decoration-line
Paste your own, or run the sample below. Analyzed in this page, with no signup and nothing stored.
Test your text-decoration-line layout across 21 email clients
Preview rendering, catch CSS issues, and see how text-decoration-line 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 Dec 6, 2023 as the last time text-decoration-line was tested in a real client, 2 years before this sync. Syncing copies that result forward, it does not re-test it. Carried in @emailens/engine data v0.14.5.