CSS property · data last changed 10 Nov 2026
[loading] in email clients
Works in 4 of 21. Not supported in Gmail, Gmail Android, Gmail iOS and 12 more. Partial in HEY Mail. Untested in Superhuman.
Safe to leave in: where it is not supported, the email renders the same.
caniemail (MIT) via @emailens/engine 0.18.22
What to do instead in Outlook Classic
There is no drop-in fix for [loading] in Outlook Classic. Design so the email still reads without it.
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[loading] 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 Android | 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 |
| Proton Mail | Not supported |
| AOL Mail | Not supported |
| Fastmail | Not supported |
| HEY Mail | Partial See caveat 2 |
| Superhuman | Untested |
Works in 4: Apple Mail, Apple Mail iOS, Samsung Mail and 1 more. Show all
| Client | Support |
|---|---|
| Apple Mail | Works See caveat 1 |
| Apple Mail iOS | Works See caveat 1 |
| Samsung Mail | Works See caveat 1 |
| Thunderbird | Works See caveat 1 |
Caveats (2)
- 1. Apple Mail, Apple Mail iOS, Samsung Mail, Thunderbird: The
loadingattribute is supported, but not confirmed whether it works according to spec. - 2. HEY Mail: Not supported. The webmail adds
loading="lazy"to all images.
Caveats as recorded by caniemail (MIT), one entry per wording.
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