Email Clients
Previewing email clients with Emailens
How Emailens previews each of the 21 supported email clients: coverage, variants, and how to read preview output.
Looking for the full per-feature CSS support data rather than how the preview works? See the Full CSS support reference on emailens.dev.
Emailens renders live previews across 21 email clients spanning webmail, desktop, and mobile platforms.
Client list
| Client | ID | Category | Engine | Dark mode | Notes |
|---|---|---|---|---|---|
| Gmail | gmail-web | Webmail | Gmail Web | Yes | |
| Gmail Android | gmail-android | Mobile | Gmail Mobile | Yes | |
| Gmail iOS | gmail-ios | Mobile | Gmail Mobile | Yes | |
| Outlook 365 | outlook-web | Webmail | Outlook Web | Yes | |
| Outlook (New) | outlook-windows | Desktop | Outlook Web | Yes | Replaces classic Outlook |
| Outlook Classic | outlook-windows-legacy | Desktop | Microsoft Word | Yes | Supported to at least 2029 |
| Outlook iOS | outlook-ios | Mobile | Outlook Mobile | Yes | |
| Outlook Android | outlook-android | Mobile | Outlook Mobile | Yes | |
| Outlook for Mac | outlook-macos | Desktop | WebKit | Yes | |
| Apple Mail | apple-mail-macos | Desktop | WebKit | Yes | |
| Apple Mail iOS | apple-mail-ios | Mobile | WebKit | Yes | |
| Yahoo Mail | yahoo-mail | Webmail | Yahoo | Yes | |
| Yahoo Mail Android | yahoo-mail-android | Mobile | Yahoo | Yes | |
| Yahoo Mail iOS | yahoo-mail-ios | Mobile | Yahoo | Yes | |
| Samsung Mail | samsung-mail | Mobile | Samsung | Yes | |
| Thunderbird | thunderbird | Desktop | Gecko | Yes | |
| HEY Mail | hey-mail | Webmail | WebKit | Yes | |
| Proton Mail | protonmail | Webmail | Proton | Yes | |
| AOL Mail | aol | Webmail | AOL | Yes | |
| Fastmail | fastmail | Webmail | Fastmail | Yes | |
| Superhuman | superhuman | Desktop | Blink | Yes |
Rendering engines
Different email clients use different rendering engines, which determines their CSS support:
- Gmail Web/Mobile , proprietary sanitiser that keeps a head
<style>block (up to 16KB, dropped in the apps for non-Google accounts) and removes web fonts, positioning and animation - Microsoft Word , Outlook Classic (legacy) uses Word to render HTML, severely limiting CSS support. No longer the Windows default from April 2026, supported to at least 2029.
- Outlook Web , browser-based engine used by Outlook.com, Outlook 365, and the new Outlook for Windows. Good CSS support.
- Outlook Mobile , Outlook for iOS and Android use Microsoft's mobile pipeline with moderate CSS support
- WebKit , Apple Mail (macOS/iOS) and Outlook for Mac use Safari's engine, supporting most modern CSS
- Gecko , Thunderbird uses Firefox's engine with excellent CSS support
- Yahoo , proprietary engine with moderate CSS support
- Samsung , proprietary mobile engine
- WebKit (HEY) , HEY Mail uses WebKit with excellent CSS support
- Blink (Superhuman) , Superhuman uses Chrome's Blink engine with excellent CSS support
- Proton , Proton Mail's privacy-focused webmail engine with good modern CSS support
- AOL , AOL Mail shares Yahoo's webmail rendering
- Fastmail , standards-based webmail engine with good CSS support
Accessing client data
import { EMAIL_CLIENTS, getClient } from "@emailens/engine";
// All clients
console.log(EMAIL_CLIENTS.length); // 21
// Single client
const newOutlook = getClient("outlook-windows");
console.log(newOutlook?.engine); // "Outlook Web"
const legacyOutlook = getClient("outlook-windows-legacy");
console.log(legacyOutlook?.engine); // "Microsoft Word"
console.log(legacyOutlook?.deprecated); // "2026-10"