How many email clients support visibility?

It works in 13 of 21, not supported in 8.

Does visibility work in Apple Mail?

visibility works in Apple Mail. Closest to Thunderbird: Apple Mail, which agrees on 219 of the 261 features both are tested on.

visibility in Thunderbird

Works visibility works in Thunderbird.

Works in 13 of 21 · not supported in 8

Which clients

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

The fix for the clients that need it

Needed in 8 of 21: Gmail, Gmail Android, Gmail iOS and 5 more.

Use conditional comments or remove hidden content

instead

5 lines

<!-- For screen readers, use font-size: 0 trick -->
<div style="font-size: 0; max-height: 0; overflow: hidden;
            mso-hide: all;" aria-hidden="true">
  Preheader text
</div>

Show the original

before

3 lines

<div style="visibility: hidden;">
  Hidden content for screen readers
</div>

A free account opens all 21 clients and keeps your checks for 7 days. Create a free account →

Your next question

Every feature in Thunderbird · visibility in every client

Questions

How many email clients support visibility?: It works in 13 of 21, not supported in 8.
Does visibility work in Apple Mail?: visibility works in Apple Mail. Closest to Thunderbird: Apple Mail, which agrees on 219 of the 261 features both are tested on.

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

Check your email, free

No signup · Five clients free, Outlook Classic included · All 21 with an account

The checker needs a computer screen.

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