Gmail Android vs Gmail iOS: CSS Support Differences

Works in Gmail Android, breaks in Gmail iOS

Each of these needs a fallback if the send reaches both.

• <dialog>
• @media orientation
• anchor-links

Works in Gmail iOS, breaks in Gmail Android

• font-stretch
• text-emphasis

Partial on one side

These render in both, but one client applies caveats the other does not. They fail quietly, which makes them the expensive ones.

• <base>
• <body>
• <button type="reset">
• <button type="submit">
• <form>
• <input type="reset">
• <input type="submit">
• <meter>
• <progress>
• <rp>
• <rt>
• <ruby>
• <select>
• <strike>
• <style>
• <ul>
• <wbr>
• [background]
• [required]
• @media
• !important
• background-blend-mode
• background-clip
• background-origin
• background-size
• box-shadow
• calc
• clamp
• clear
• css-comments
• display
• fit-content
• float
• font-size-adjust
• gap
• html5-semantics
• linear-gradient
• list-style
• margin
• max
• meta-color-scheme
• min
• mix-blend-mode
• object-fit
• object-position
• overflow
• radial-gradient
• rgb
• rgba
• system-ui
• text-align
• text-decoration
• text-decoration-color
• text-indent
• text-overflow
• text-underline-position
• unit-initial
• white-space
• word-break
• writing-mode
• :adjacent-sibling
• :attribute-selector
• :chaining
• :child-combinator
• :class-selector
• :descendant-combinator
• :general-sibling
• :grouping
• :hover
• :id-selector
• :type-selector
• :universal-selector
• display:flex
• display:grid

Where the divergence sits

Two pairs with the same headline number can be different problems. For these two it concentrates in CSS Properties.

• CSS Properties 35
• HTML Elements 18
• Pseudo-Classes & Selectors 12
• CSS Functions 7
• HTML & Email Structure 3
• CSS At-Rules 2

13 of these already have a fix

Each links to a copy-paste snippet that keeps the feature working in Gmail iOS without dropping it in Gmail Android.

• <form>
• <style>
• @media
• background-size
• box-shadow
• float
• gap
• linear-gradient
• object-fit
• overflow
• word-break
• display:flex
• display:grid

Check your own HTML against both

Questions

How different are Gmail Android and Gmail iOS?

They disagree on 79 of the 300 features verified in both clients, or 26%. 98 features render in both and are the safe intersection to build on.

What works in Gmail Android but not Gmail iOS?

3 features, including <dialog>, @media orientation, anchor-links. Each needs a fallback if the send reaches both clients.

Which engines are these two clients using?

Gmail Android renders with Gmail Mobile; Gmail iOS renders with Gmail Mobile. Where two clients share an engine the divergence is usually configuration, and where they do not it is the engine itself.

Is this measured in the real clients?

No. These are documented support levels derived from caniemail.com (MIT-licensed), carried in @emailens/engine data version 0.18.22 and last synced Nov 10, 2026. That sync date is not a test date: caniemail's own per-feature tests run from Feb 28, 2019 to Sep 16, 2026. Anything described as a transform is applied per those documented rules rather than captured from a real client.