CSS Properties

box-shadow

CSS property · 12 supported, 2 partial, 7 unsupported across 21 clients

12 of 21 email clients render box-shadow fully (Sep 2, 2026 data); it breaks outright in Gmail, Outlook (New), Outlook Classic and 4 more.

4/7 webmail, 4/6 desktop, 4/8 mobile clients support box-shadow fully.
Unsupported in Gmail, Outlook (New), Outlook Classic, Yahoo Mail and 3 more.
Partial in Gmail Android, Gmail iOS, behavior differs from browsers, test before relying on it.
Outlook Classic (Word engine, supported to at least 2029) does not fully support box-shadow, and its replacement changes little here; see the deprecation diff.
Documented before/after fixes on this page cover 21 clients, including Gmail and Gmail Android.
Across all clients, only 6 of 298 tracked HTML/CSS features render identically everywhere.

Source: caniemail.com (MIT), via the Emailens engine. Last tested upstream Dec 20, 2023, synced by Emailens Sep 2, 2026.

Client Support

Client	Category	Engine	Support
Gmail	webmail	Gmail Web	Unsupported
Gmail Android	mobile	Gmail Mobile	Partial^{See caveat 1}
Gmail iOS	mobile	Gmail Mobile	Partial^{See caveat 1}
Outlook 365	webmail	Outlook Web	Supported
Outlook (New)	desktop	Outlook Web	Unsupported
Outlook Classic	desktop	Microsoft Word	Unsupported
Outlook iOS	mobile	Outlook Mobile	Supported
Outlook Android	mobile	Outlook Mobile	Supported
Outlook for Mac	desktop	WebKit	Supported
Apple Mail	desktop	WebKit	Supported
Apple Mail iOS	mobile	WebKit	Supported
Yahoo Mail	webmail	Yahoo	Unsupported
Yahoo Mail Android	mobile	Yahoo	Unsupported
Yahoo Mail iOS	mobile	Yahoo	Unsupported
Samsung Mail	mobile	Samsung	Supported
Thunderbird	desktop	Gecko	Supported
HEY Mail	webmail	WebKit	Supported
Proton Mail	webmail	Proton	Supported
AOL Mail	webmail	AOL	Unsupported
Fastmail	webmail	Fastmail	Supported
Superhuman	desktop	Blink	Supported

Documented caveats (1)

1.Gmail Android, Gmail iOS: Partial. Only supported with non Google accounts.

Caveats recorded by caniemail.com (MIT) and carried verbatim, one entry per wording rather than per client.

Client-by-client behaviour for box-shadow

Fully supports box-shadow (12): Outlook 365, Outlook iOS, Outlook Android, Outlook for Mac, Apple Mail, Apple Mail iOS, Samsung Mail, Thunderbird, HEY Mail, Proton Mail, Fastmail, Superhuman.

Partial support (2): Gmail Android, Gmail iOS. Expect rendering quirks unique to each engine. Partial support typically means a subset of values, an ignored shorthand, or sanitizer-specific rewrites.

No support (7): Gmail, Outlook (New), Outlook Classic, Yahoo Mail, Yahoo Mail Android, Yahoo Mail iOS, AOL Mail. Plan fallbacks for these clients before relying on box-shadow in production sends.

Fixes & Workarounds

Gmail

Unsupported

Use border styling as an alternative to box-shadow.

Before (Broken)

before.html

3 lines

.card {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

After (Fixed)

fixed.html

5 lines

.card {
  border: 1px solid #e0e0e0;
  /* box-shadow as progressive enhancement */
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

Use border as a fallback for box-shadow

Outlook (New)

Unsupported

Use border styling as an alternative to box-shadow.

Before (Broken)

before.html

3 lines

.card {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

After (Fixed)

fixed.html

5 lines

.card {
  border: 1px solid #e0e0e0;
  /* box-shadow as progressive enhancement */
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

Use border as a fallback for box-shadow

Outlook Classic

Unsupported

Use border styling as an alternative to box-shadow.

Before (Broken)

before.html

3 lines

.card {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

After (Fixed)

fixed.html

5 lines

.card {
  border: 1px solid #e0e0e0;
  /* box-shadow as progressive enhancement */
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

Use border as a fallback for box-shadow

Yahoo Mail

Unsupported

Use border styling as an alternative to box-shadow.

Before (Broken)

before.html

3 lines

.card {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

After (Fixed)

fixed.html

5 lines

.card {
  border: 1px solid #e0e0e0;
  /* box-shadow as progressive enhancement */
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

Use border as a fallback for box-shadow

Yahoo Mail Android

Unsupported

Use border styling as an alternative to box-shadow.

Before (Broken)

before.html

3 lines

.card {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

After (Fixed)

fixed.html

5 lines

.card {
  border: 1px solid #e0e0e0;
  /* box-shadow as progressive enhancement */
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

Use border as a fallback for box-shadow

Yahoo Mail iOS

Unsupported

Use border styling as an alternative to box-shadow.

Before (Broken)

before.html

3 lines

.card {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

After (Fixed)

fixed.html

5 lines

.card {
  border: 1px solid #e0e0e0;
  /* box-shadow as progressive enhancement */
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

Use border as a fallback for box-shadow

AOL Mail

Unsupported

Use border styling as an alternative to box-shadow.

Before (Broken)

before.html

3 lines

.card {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

After (Fixed)

fixed.html

5 lines

.card {
  border: 1px solid #e0e0e0;
  /* box-shadow as progressive enhancement */
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

Use border as a fallback for box-shadow

Gmail Android

Partial

Use border styling as an alternative to box-shadow.

Before (Broken)

before.html

3 lines

.card {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

After (Fixed)

fixed.html

5 lines

.card {
  border: 1px solid #e0e0e0;
  /* box-shadow as progressive enhancement */
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

Use border as a fallback for box-shadow

Gmail iOS

Partial

Use border styling as an alternative to box-shadow.

Before (Broken)

before.html

3 lines

.card {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

After (Fixed)

fixed.html

5 lines

.card {
  border: 1px solid #e0e0e0;
  /* box-shadow as progressive enhancement */
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

Use border as a fallback for box-shadow

Production guidance for box-shadow

box-shadow is a CSS property. Across the email client matrix, 12 of 21 tracked clients support it fully, 2 only partially, and 7 not at all. The clients most likely to require a workaround for this feature are Gmail, Outlook (New), Outlook Classic. Each of them needs a tailored fallback. See the per-client examples above for the specific code fix Emailens recommends.

When in doubt, ship a baseline that renders without box-shadow and treat it as progressive enhancement on clients where support is verified. Emailens automatically detects cross-client divergence on this feature when you preview an email, so you can see exactly which template paths break before a campaign goes out.

Related Features

!important accent-color align-items animation aspect-ratio backdrop-filter background background-blend-mode

Check your own HTML for box-shadow

Paste your own, or run the sample below. Analyzed in this page, with no signup and nothing stored.

Zero-Friction Engine Preview

Test your box-shadow layout across 21 email clients

Preview rendering, catch CSS issues, and see how box-shadow displays across Outlook, Gmail, and Apple Mail. Free, no account needed.

Instant live preview · No signup required · 21 email engines

Last tested upstream: Dec 20, 2023 · Last synced by Emailens: Sep 2, 2026

caniemail.com (MIT) records Dec 20, 2023 as the last time box-shadow was tested in a real client, 2 years before this sync. Syncing copies that result forward, it does not re-test it. Carried in @emailens/engine data v0.12.2.