What is a Browser Compatibility Checker?
A browser compatibility checker tells you whether a CSS property, JavaScript feature, or HTML element is supported across Chrome, Firefox, Safari, Edge, and mobile browsers. Before shipping code that uses a newer web platform feature, you need to know if your users' browsers will actually support it.
Powered by the MDN Browser Compatibility Data — the same data that powers Mozilla's official compatibility tables — this tool gives you accurate, up-to-date support information across all major browsers, including mobile variants. Search by feature name or browse by category to find exactly what you need.
Why Check Browser Compatibility?
The web evolves fast. New CSS features, JavaScript APIs, and HTML elements ship in modern browsers regularly — but not all browsers adopt them at the same pace. Safari has historically lagged behind Chrome on many features. Firefox ships things Chrome doesn't yet have. And mobile browsers sometimes behave differently from their desktop counterparts.
Shipping a feature without checking compatibility can mean broken layouts, JavaScript errors, or missing functionality for a significant chunk of your users. A quick compatibility check before writing the code saves hours of debugging after the fact. This tool makes that check instant.
How To Use It
1. Search by Feature Name
Type a feature name into the search bar — for example container queries, fetch, or dialog. Results appear instantly showing support across all major browsers.
2. Browse by Category
Not sure what a feature is called? Browse by category — CSS, JavaScript, HTML, or Web APIs. Each category has featured shortcuts for the most commonly checked items so you can jump straight to what matters.
3. Read the Support Grid
Click any feature card to expand it and see a full browser support grid. Green means fully supported with the version it was introduced. Yellow means partial support or behind a flag. Red means not supported.
4. Check Desktop & Mobile
The support grid is split into Desktop (Chrome, Firefox, Safari, Edge, Opera) and Mobile (iOS Safari, Chrome Android, Firefox Android) so you can make informed decisions for both contexts.
Who Is This For?
Frontend Developers
The primary audience. Before using a new CSS property like :has() or a JS API like structuredClone, check if your target browsers support it — or if you need a polyfill or fallback.
UI/UX Designers
Designing with modern CSS features like container queries or subgrid? Verify with your dev team that the browsers your audience uses actually support them before finalizing designs.
Technical Writers & Educators
Writing tutorials or documentation about web features? Always verify current browser support before publishing. What was experimental last year might be fully supported now — or vice versa.
QA Engineers
Investigating a cross-browser bug? Check if the feature in question has known partial support or flag requirements in a specific browser — it often explains the issue immediately.
What's Covered?
The tool covers thousands of features across four major categories:
- —CSS: Grid, Flexbox, Container Queries, Custom Properties, Cascade Layers,
:has(), Subgrid, Nesting,color-mix(), Scroll Snap, Clip Path, and hundreds more. - —JavaScript: Promises, async/await, Optional Chaining, Nullish Coalescing, BigInt, WeakRef,
structuredClone,Array.at(),Object.hasOwn(), and more. - —HTML:
<dialog>,<details>,<datalist>,<template>,<picture>, and all major HTML5 elements. - —Web APIs: IntersectionObserver, ResizeObserver, MutationObserver, WebSockets, Geolocation, Clipboard API, Web Workers, Service Workers, WebAssembly, and more.
Benefits
Always Up to Date
Powered by MDN Browser Compatibility Data — the most actively maintained compatibility dataset on the web, updated continuously by Mozilla and contributors worldwide.
Desktop & Mobile
Support data covers both desktop browsers and their mobile counterparts. iOS Safari and Chrome Android often have different support levels than their desktop versions.
Version Numbers
Where available, you'll see exactly which version of each browser first added support. This helps you determine whether you need a polyfill based on your browser support targets.
Links to MDN Docs
Every feature card links directly to its MDN documentation page and spec — so you can go from compatibility check to full reference documentation in one click.
FAQ
Is this the same as caniuse.com?+
Similar concept but different data source. caniuse.com uses its own curated dataset focused on broader usage statistics. This tool uses MDN Browser Compatibility Data which covers a wider range of features — especially JavaScript APIs and HTML elements — and is updated more frequently.
What does "Partial" support mean?+
Partial support means the browser implements the feature but only behind a flag that users must manually enable, or supports only a subset of the feature's functionality. You generally shouldn't rely on partial support in production.
How do I know which browsers to target?+
That depends on your audience. Check your analytics for the browsers your users actually use. A developer tool can safely target modern browsers only. A consumer product serving a global audience may need to support older Safari versions on iOS.
What if a feature I need isn't supported everywhere?+
You have a few options: use a polyfill to add support in older browsers, use a progressive enhancement approach where the feature enhances the experience but isn't required, use @supports in CSS to apply styles conditionally, or choose an alternative feature with broader support.
How often is the data updated?+
The MDN Browser Compatibility Data package is updated regularly as browsers ship new versions. The tool pulls from the npm package which reflects the latest published data.
Can I check support for a specific browser version?+
The tool shows the minimum version that added support for a feature. If your target is a specific version, compare it against the "added in version X" shown in the support grid.
Ship with Confidence
Check browser support before you write the code, not after you ship it. Search any CSS, JavaScript, or HTML feature above and get instant compatibility data across all major browsers.