Baseline gets a new definition

When Baseline launched at Google I/O this year, it established a clear signal for whether a web platform feature was ready to use. The original definition was straightforward: a feature became part of Baseline when it was supported in the current and previous version of all major browsers—Chrome, Edge, Firefox, and Safari. But after feedback from the community and work within the WebDX Community Group, that definition has been refined.

The key insight driving the change is that there are two distinct, meaningful moments in a feature's lifecycle. The first is when a feature becomes interoperable across all major engines. The second is the point at which most sites can safely adopt it, without support concerns. The first moment is easy to pin down; the second depends heavily on your audience and how quickly your users upgrade.

Newly available and widely available

To reflect these two moments, the WebDX Community Group's governance group—formed to oversee the Web Features project—has redefined Baseline around two stages:

  • Newly available: A feature enters Baseline as newly available once it is interoperable across the main browsers.
  • Widely available: A feature reaches this stage when it is generally safe to use, set at 30 months after the newly available point.

The core browser set has also been expanded to explicitly include mobile versions of browsers. A feature will not be considered newly available until it works in Safari (macOS and iOS), Firefox (Desktop and Android), Chrome (Desktop and Android), and Edge (Desktop).

Why 30 months?

The widely available line can never be perfect for every site. However, data on browser version adoption shows that for most features, 30 months from interoperability is enough time to reach roughly 95% of users globally. You may be comfortable using a feature much earlier than that, but after the 30-month window it becomes unlikely that support will be a blocker. For many teams, your own practical "safe to use" line will fall somewhere between newly available and widely available. The newly available moment is still useful as a signal that a feature is worth learning, so you are prepared to use it in production once it becomes more broadly adopted.

What's next

The next step is to map the entire web platform in the Web Features dataset so the Baseline status can be rolled out on MDN and other properties. That work is ongoing and is expected to be completed during 2024. MDN has already announced the change and is rolling out new Baseline badges across its pages. Similar badges for Baseline status are planned for web.dev and developer.chrome.com.