mailto-links
CSS property · 17 supported, 3 partial, 0 unsupported across 21 clients
mailto-links splits the field: 17 full, 3 partial of 21 clients as of Oct 14, 2026, the partials (Yahoo Mail Android, Proton Mail, AOL Mail) are where sends go wrong.
- 5/7 webmail, 5/6 desktop, 7/8 mobile clients support mailto-links fully.
- Partial in Yahoo Mail Android, Proton Mail, AOL Mail, 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 May 20, 2021, 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 | 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 | PartialSee caveat 1 |
| Yahoo Mail iOS | mobile | Yahoo | Supported |
| Samsung Mail | mobile | Samsung | Supported |
| Thunderbird | desktop | Gecko | Supported |
| HEY Mail | webmail | WebKit | Supported |
| Proton Mail | webmail | Proton | PartialSee caveat 1 |
| AOL Mail | webmail | AOL | PartialSee caveat 1 |
| Fastmail | webmail | Fastmail | Supported |
| Superhuman | desktop | Blink | Unknown |
Documented caveats (1)
- 1.Yahoo Mail Android, Proton Mail, AOL Mail: Partial.
bccis not supported.
Caveats recorded by caniemail.com (MIT) and carried verbatim, one entry per wording rather than per client.
Client-by-client behaviour for mailto-links
Fully supports mailto-links (17): Gmail, Gmail Android, Gmail iOS, Outlook 365, Outlook (New), Outlook Classic, Outlook iOS, Outlook Android, Outlook for Mac, Apple Mail, Apple Mail iOS, Yahoo Mail, Yahoo Mail iOS, Samsung Mail, Thunderbird, HEY Mail, Fastmail.
Partial support (3): Yahoo Mail Android, Proton Mail, AOL Mail. Expect rendering quirks unique to each engine. Partial support typically means a subset of values, an ignored shorthand, or sanitizer-specific rewrites.
Behaviour unverified in: Superhuman.
Fixes & Workarounds
Yahoo Mail Android
Partial"mailto-links" is not supported in this email client.
Proton Mail
Partial"mailto-links" is not supported in this email client.
AOL Mail
Partial"mailto-links" is not supported in this email client.
Related Features
Check your own HTML for mailto-links
Paste your own, or run the sample below. Analyzed in this page, with no signup and nothing stored.
Test your mailto-links layout across 21 email clients
Preview rendering, catch CSS issues, and see how mailto-links 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 20, 2021 as the last time mailto-links 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 v0.14.5.