Emailens
Reference

CSS Properties

CSS support levels for each property across all 13 email clients (250+ properties tracked).

Support levels

Each CSS property is assigned one of four support levels per client:

LevelMeaning
supportedFully supported, renders as expected
partialSupported with caveats or visual differences
unsupportedNot supported, property is stripped or ignored
unknownNot tested or behavior is inconsistent

Common properties

Layout

PropertyGmailOutlook 365Outlook WinApple MailYahooSamsungThunderbird
display: blocksupportedsupportedsupportedsupportedsupportedsupportedsupported
display: flexsupportedsupportedunsupportedsupportedsupportedsupportedsupported
display: gridunsupportedunsupportedunsupportedsupportedunsupportedunsupportedsupported
floatsupportedsupportedunsupportedsupportedpartialsupportedsupported
positionunsupportedpartialunsupportedpartialpartialpartialsupported

Box model

PropertyGmailOutlook 365Outlook WinApple MailYahooSamsungThunderbird
marginpartialsupportedpartialsupportedsupportedsupportedsupported
paddingsupportedsupportedpartialsupportedsupportedsupportedsupported
bordersupportedsupportedpartialsupportedsupportedsupportedsupported
border-radiussupportedsupportedunsupportedsupportedpartialsupportedsupported
box-shadowunsupportedsupportedunsupportedsupportedunsupportedsupportedsupported
widthsupportedsupportedsupportedsupportedsupportedsupportedsupported
max-widthsupportedsupportedpartialsupportedsupportedsupportedsupported

Typography

PropertyGmailOutlook 365Outlook WinApple MailYahooSamsungThunderbird
font-familysupportedsupportedsupportedsupportedsupportedsupportedsupported
font-sizesupportedsupportedsupportedsupportedsupportedsupportedsupported
line-heightsupportedsupportedpartialsupportedsupportedsupportedsupported
letter-spacingsupportedsupportedunsupportedsupportedsupportedsupportedsupported
text-alignsupportedsupportedsupportedsupportedsupportedsupportedsupported
text-decorationsupportedsupportedsupportedsupportedsupportedsupportedsupported

Color and background

PropertyGmailOutlook 365Outlook WinApple MailYahooSamsungThunderbird
colorsupportedsupportedsupportedsupportedsupportedsupportedsupported
background-colorsupportedsupportedsupportedsupportedsupportedsupportedsupported
background-imagesupportedsupportedpartialsupportedpartialsupportedsupported
linear-gradientunsupportedunsupportedunsupportedsupportedunsupportedunsupportedsupported
opacityunsupportedsupportedunsupportedsupportedsupportedsupportedsupported

Selectors and at-rules

FeatureGmailOutlook 365Outlook WinApple MailYahooSamsungThunderbird
<style> blockpartialsupportedpartialsupportedsupportedsupportedsupported
@media queriespartialpartialunsupportedsupportedpartialpartialsupported
:hover pseudounsupportedsupportedunsupportedsupportedunsupportedpartialsupported
@font-faceunsupportedunsupportedpartialsupportedunsupportedsupportedsupported

Programmatic access

Use @emailens/engine to query support levels programmatically:

import { analyzeEmail, generateCompatibilityScore } from "@emailens/engine";

const warnings = analyzeEmail(html);
const scores = generateCompatibilityScore(warnings);

// Scores include per-client breakdown
// { "gmail-web": { score: 85, errors: 0, warnings: 3, info: 1 }, ... }

See the full CSS Support Matrix in the engine docs for the complete 250+ property reference, auto-synced from caniemail.com data.

Client Reference

Complete reference for all 13 supported email clients with their properties.

Changelog

Release notes and version history for Emailens.

On this page

Support levelsCommon propertiesLayoutBox modelTypographyColor and backgroundSelectors and at-rulesProgrammatic access