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text-shadow in Fastmail

Works text-shadow works in Fastmail.

Works in 12 of 21 · not supported in 9

Which clients
Works
Outlook 365, Outlook Android, Apple Mail, Apple Mail iOS, Yahoo Mail iOS, Samsung Mail, Thunderbird, HEY Mail, Proton Mail, AOL Mail, Fastmail, Superhuman
Not supported
Gmail, Gmail Android, Gmail iOS, Outlook (New), Outlook Classic, Outlook iOS, Outlook for Mac, Yahoo Mail, Yahoo Mail Android

The fix for the clients that need it

Needed in 9 of 21: Gmail, Gmail Android, Gmail iOS and 6 more.

Use font-weight or border-bottom as alternatives to text-shadow

instead
.glow {
  /* text-shadow is not supported in Gmail, Outlook, Yahoo.
     Use font-weight or letter-spacing for emphasis instead. */
  font-weight: bold;
  letter-spacing: 0.5px;
}
Show the original
before
.glow {
  text-shadow: 0 0 10px rgba(255, 255, 255, 0.5);
}

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Your next question

Every feature in Fastmail · text-shadow in every client

Questions

How many email clients support text-shadow?
It works in 12 of 21, not supported in 9.
Does text-shadow work in Apple Mail?
text-shadow works in Apple Mail. Closest to Fastmail: Apple Mail, which agrees on 192 of the 235 features both are tested on.

To see what in your email Fastmail does not support, paste the whole email.

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Real captures 14 Oct 2026 on 11 installs · caniemail (MIT) via @emailens/engine 0.18.22 · tested upstream 28 Feb 2019 · data last changed 10 Nov 2026 · Outlook (New) cells are the engine's mapping