Chapter 1 · Practice 1 of 4
Check Baseline status before you rely on a feature
Why it matters
"Can I use this?" used to mean digging through compatibility tables. web.dev's Baseline gives a simpler answer, based on the core browser set: Chrome and Edge, Firefox, and Safari, on desktop and mobile.
| Status | Meaning |
|---|---|
| Limited availability | Not yet in every core browser |
| Newly available | Works in the latest version of every core browser |
| Widely available | 30 months have passed since it became Newly available |
Most sites can use Widely available features without a second thought. Newly available features are fine when your users are on up to date browsers, or when the feature degrades gracefully, for example a nicer animation that simply does not run on an old browser.
MDN shows the Baseline status at the top of each reference page. For example, :has() is marked Widely available, and @property was marked Newly available from July 2024.
Do
- Check the Baseline badge on MDN before adding a feature to a shared component
- Write a fallback first when a feature has limited availability
Avoid
- Shipping a limited availability feature in a critical layout with no fallback