What Baseline means for web developers
Evergreen browsers ship new features constantly, and that pace has made "browser support" far harder to communicate than it was in the days of fixed release trains like Internet Explorer 11. When a browser ships every four weeks and every engine moves at its own rhythm, the old line in the sand disappears. Announced at Google I/O 2023, Baseline offers a shared definition of what is safe to use today.
The concept is simple: a feature is in Baseline when it is fully supported in the most recent two versions of all major browsers. That gives developers a concrete answer to the question "can I use this yet?" without auditing release notes across engines. If your library states that everything it uses is part of Baseline, that is an unambiguous claim. If you are proposing a new application, you can tell stakeholders that support maps to Baseline rather than to a list of individual browser versions.
A continuous line, with annual snapshots
Baseline is not a static target. New features join every month as the major engines reach interoperable support, so the set keeps growing. To make conversations with stakeholders easier, yearly snapshots will be published: saying "supported as of Baseline 24" pins a project to the features that had reached Baseline in a particular year.
Expect to see the label in two places right away: feature pages on MDN (for example, the CSS grid documentation) and articles on web.dev.
Cleaning up the communication channels
The initiative grew partly out of self-examination. web.dev and developer.chrome.com were mixing experimental APIs, single-browser features, and stable platform pieces, which only deepened the confusion. Those sites are now being split by intent. web.dev covers the stable web, the features that are Baseline or near it, plus cross-browser work such as the newly interoperable series and Interop 2023 updates. developer.chrome.com focuses on what Chrome is bringing to the platform, including things that are Chrome-only or experimental, with support data attached so the status is unambiguous. Every publication and conference talk from the team is supposed to carry clear browser support info as well.
Documentation also gets attention. Features shipping in Chrome this year, such as the View Transitions API and WebGPU, have documentation on MDN, and the team is supporting Open Web Docs, which contributes MDN documentation for the whole platform.
Backed by the WebDX Community Group
The cross-company work behind Baseline is happening in the W3C WebDX Community Group, which assembled after the Interop 2022 and 2023 collaborations. The group maintains a feature set, a structured way of grouping web platform features along with their support status, and that data drives Baseline. The point of this group is cooperation rather than a Chrome-only view, which matters because a support label is only useful if every engine is treated the same way.
What ships next
The rollout has immediate and longer-range parts. For readers, web.dev articles will indicate which features they use are part of Baseline, so you won't invest in a tutorial and then discover mid-way that it relies on a feature that only one engine supports. The project will also publish widgets that can be embedded in your own documentation or library pages to show Baseline support status.
Inside the teams, the work is to move Chrome features into Baseline as efficiently as possible, via interoperability with the other engines rather than by holding anything back. There will be ongoing feedback collection from developers to test how well the definition works in practice, with the WebDX Community Group as the place to raise suggestions. The Baseline page and the group are both live today for anyone who wants to participate.
