How many email clients support visibility?

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

Does visibility work in Apple Mail iOS?

visibility works in Apple Mail iOS. Closest to Apple Mail: Apple Mail iOS, which agrees on 284 of the 298 features both are tested on.

visibility in Apple Mail

Works visibility works in Apple Mail.

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>

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What Apple Mail does with visibility

The Emailens probe for visibility on a real install counted as Apple Mail, captured 14 Oct 2026. It shows the probe, not the fix. Where visibility is supported it shows: a, gap, b (no hidden word).

The Emailens probe for visibility on a real Apple Mail (macOS) — Apple Mail

The same probe in the Emailens live preview of Apple Mail — Apple Mail

Every account includes one free real-device check in classic Outlook, Outlook for Mac and Apple Mail, after you verify your email and run one preview, while this month's free capacity lasts. How real-device checks work →

caniemail record, tested upstream 28 Feb 2019

Buggy. visibility:collapse applied to a <tr> only hides content and does not "remove" it from layout.

Your next question

Every feature in Apple Mail · 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 iOS?: visibility works in Apple Mail iOS. Closest to Apple Mail: Apple Mail iOS, which agrees on 284 of the 298 features both are tested on.

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

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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