Baseline update: Browserslist integration and September’s feature milestones

September was a heavy month for Baseline, with a significant tooling integration landing alongside a large batch of features moving into both Newly and Widely available status. Here’s what changed.

Browserslist adds native Baseline queries

Browserslist now includes built-in queries for Baseline targets, removing the need for the previous browserslist-baseline-config npm package in your project toolchains. You can target specific availability levels directly, such as Baseline Widely available:

baseline widely available

or Baseline Newly available:

baseline newly available

You can also restrict results to a specific Baseline year, with support ranging from 2015 up to the current year:

baseline 2022

For projects that need to account for downstream browsers, append with downstream to any valid Baseline query:

baseline widely available with downstream

Because these queries work anywhere Browserslist is used, most modern toolchains can adopt them immediately. You can test query behavior on the Browserslist website, and the earlier announcement covers the integration in more detail.

September’s Newly available features

Five features reached Baseline Newly available status this month:

  • content-visibility
  • <link rel="dns-prefetch">
  • Unsanitized HTML parsing methods (Document.parseHTMLUnsafe())
  • URLPattern
  • Uint8Array base64 and hex conversion

Twenty-one features reach Widely available

September was an outlier in the volume of features graduating to Baseline Widely available. The full list spans CSS, JavaScript, and platform APIs:

  • Constructable stylesheets
  • Fetch metadata request header
  • font-synthesis-small-caps, font-synthesis-style, and font-synthesis-weight
  • Form-associated custom elements
  • Import maps
  • Media query range syntax
  • messageerror event
  • Notifications from service workers and installed apps
  • Offscreen canvas
  • Origin private file system
  • outline CSS property
  • pdfViewerEnabled
  • Push messages
  • requestAnimationFrame() in workers
  • Resource size (PerformanceResourceTiming)
  • Screen orientation API
  • Server timing
  • Imperative slot assignment
  • Fixed-width SIMD (Wasm)

This wave underscores how interoperable implementations compound over time, moving large groups of features into universal availability at once.

Interop 2026 proposals closed

The Interop Project, which coordinates cross-vendor implementation work and bug fixes, has wrapped up proposal submissions for the 2026 focus areas. Browser vendors are now reviewing which features and problem areas to prioritize. Expect announcements from Google and other vendors in upcoming digests.

Baseline timeline tool gains keyboard controls

The Baseline timeline tool, which charts feature availability, now includes keyboard shortcuts. Press ? on the site to view them:

  • w: filter Widely available features
  • n: filter Newly available features
  • l: filter limited availability features
  • d: filter deprecated features
  • i: filter features with interop tags
  • c: scroll to current month
  • r: reset all filters
  • p: toggle feature predictions

These shortcuts make it faster to construct custom views of Baseline features matching your criteria.