HTML element · data last changed 10 Nov 2026
<dialog> in email clients
Works in 5 of 21. Not supported in Gmail, Gmail iOS, Outlook 365 and 12 more. Untested in Superhuman.
Your reader in Outlook Classic sees the email without <dialog>, even if it looks right where you tested it.
caniemail (MIT) via @emailens/engine 0.18.22
What to do instead in Outlook Classic
Avoid <dialog> in production email. If you need a 'modal' visual treatment, build a styled card with table cells and let it render inline in the email flow.
There is no drop-in fix for <dialog> in Outlook Classic. Design so the email still reads without it.
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<dialog> is not among the 24 features we have screenshotted on real installs. The ones we have →
All 21 clients, problems first
| Client | Support |
|---|---|
| Gmail | Not supported |
| Gmail iOS | Not supported |
| Outlook 365 | Not supported |
| Outlook (New) | Not supported |
| Outlook Classic | Not supported |
| Outlook iOS | Not supported |
| Outlook Android | Not supported |
| Outlook for Mac | Not supported |
| Yahoo Mail | Not supported |
| Yahoo Mail Android | Not supported |
| Yahoo Mail iOS | Not supported |
| HEY Mail | Not supported |
| Proton Mail | Not supported |
| AOL Mail | Not supported |
| Fastmail | Not supported |
| Superhuman | Untested |
Works in 5: Gmail Android, Apple Mail, Apple Mail iOS and 2 more. Show all
| Client | Support |
|---|---|
| Gmail Android | Works |
| Apple Mail | Works |
| Apple Mail iOS | Works |
| Samsung Mail | Works |
| Thunderbird | Works |
How <dialog> behaves
The <dialog> element represents a modal or non-modal dialog. It is unsupported in essentially every email client because email is not an interactive surface. Including <dialog> in email markup is harmless, the content inside renders as a regular block, but the open/close behavior never works.
- <dialog> renders as a block-level element with default styling, but no clients honor its open/show behavior.
- Most clients ignore the open attribute entirely.
- AMP for Email provides interactive lightboxes through dedicated AMP components, not native <dialog>.
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