What does it mean to say a web platform feature is Baseline?

Features on the web platform can sometimes be indicated as “Baseline”. For example, if you search for flex on caniuse.com here, you’ll see a Baseline label:

When a feature is flagged as Baseline, it essentially means it’s well supported in all the major browsers without needing any prefixes like -webkit-placeholder or any polyfills. In other words, you can safely use that feature without too much thought.

The major browsers are considered the following:

• Chrome (desktop & Android)
• Edge
• Firefox (desktop & Android)
• Safari (macOS and iOS)

How do things become Baseline?

A feature goes through two stages:

• Newly available. The feature works across the latest devices and browser versions. It might not work in older devices or browsers. Indicated with a blue icon.
• Widely available. The feature is well established and works across many devices and browser versions. It’s been available for at least 2.5 years. Indicated with a green icon.

Prior to being Newly available, the feature is considered in the Limited availability stage when it’s not yet supported across the major browsers.

Who decides what’s Baseline?

The Baseline project was originated by the Chrome team but is now managed by the WebDX Community Group.