<bdi>
HTML element · 7 supported, 0 partial, 13 unsupported across 21 clients
As of Oct 14, 2026, <bdi> fails or degrades in 14 of 21 email clients, treat it as progressive enhancement, never structure.
- 2/7 webmail, 3/6 desktop, 2/8 mobile clients support <bdi> fully.
- Unsupported in Gmail, Gmail Android, Gmail iOS, Outlook 365 and 9 more.
- Outlook Classic (Word engine, supported to at least 2029) does not fully support <bdi>, 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 Feb 28, 2019, synced by Emailens Oct 14, 2026.
The <bdi> element isolates a span of text whose directionality may differ from its surroundings. It is most useful in mixed-direction content (English + Arabic, Hebrew + English) but email client support is uneven. Modern WebKit clients honor it; Outlook and many older clients treat it as a generic <span>.
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 | Unsupported |
| 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 | Unsupported |
| Proton Mail | webmail | Proton | Supported |
| AOL Mail | webmail | AOL | Unsupported |
| Fastmail | webmail | Fastmail | Supported |
| Superhuman | desktop | Blink | Unknown |
Client-by-client behaviour for <bdi>
Fully supports <bdi> (7): Outlook for Mac, Apple Mail, Apple Mail iOS, Samsung Mail, Thunderbird, Proton Mail, Fastmail.
No support (13): Gmail, Gmail Android, Gmail iOS, Outlook 365, Outlook (New), Outlook Classic, Outlook iOS, Outlook Android, Yahoo Mail, Yahoo Mail Android, Yahoo Mail iOS, HEY Mail, AOL Mail. Plan fallbacks for these clients before relying on <bdi> in production sends.
Behaviour unverified in: Superhuman.
When to use <bdi> in email
- Embedding user-generated names in a localized email where direction may be unknown.
- Mixing English brand identifiers within Arabic body copy.
- Editorial content that quotes right-to-left strings inside left-to-right paragraphs.
Rendering behaviour and edge cases
- Apple Mail and modern Chromium-based Gmail honor <bdi> directionality isolation.
- Outlook on Windows treats <bdi> as a regular inline element.
- <bdi> is purely semantic, visual results match <span> in non-supporting clients.
Recommended fallback strategy
Use <bdi> liberally in mixed-direction content as a no-cost progressive enhancement. For visually critical bidi handling, also set explicit dir attributes on the surrounding elements to give clients the strongest possible directional signal.
Fixes & Workarounds
Gmail
Unsupported`<bdi>` is not supported in this email client.
Gmail Android
Unsupported`<bdi>` is not supported in this email client.
Gmail iOS
Unsupported`<bdi>` is not supported in this email client.
Outlook 365
Unsupported`<bdi>` is not supported in this email client.
Outlook (New)
Unsupported`<bdi>` is not supported in this email client.
Outlook Classic
Unsupported`<bdi>` is not supported in this email client.
Outlook iOS
Unsupported`<bdi>` is not supported in this email client.
Outlook Android
Unsupported`<bdi>` is not supported in this email client.
Yahoo Mail
Unsupported`<bdi>` is not supported in this email client.
Yahoo Mail Android
Unsupported`<bdi>` is not supported in this email client.
Yahoo Mail iOS
Unsupported`<bdi>` is not supported in this email client.
HEY Mail
Unsupported`<bdi>` is not supported in this email client.
AOL Mail
Unsupported`<bdi>` is not supported in this email client.
Related Features
Check your own HTML for <bdi>
Paste your own, or run the sample below. Analyzed in this page, with no signup and nothing stored.
Test your <bdi> layout across 21 email clients
Preview rendering, catch CSS issues, and see how <bdi> 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 Feb 28, 2019 as the last time <bdi> was tested in a real client, 7 years before this sync. Syncing copies that result forward, it does not re-test it. Carried in @emailens/engine data v0.14.5.