Baseline update: Interop 2025, new tooling, and a Popover API correction

February was a dense month for Baseline-related news, spanning the official launch of Interop 2025, new community tooling, and a notable correction to the Popover API's Baseline status.

Interop 2025 launches

The Interop 2025 project is now officially underway, with Apple, Mozilla, Microsoft, Google, Igalia, and Bocoup all publishing announcements. The project defines cross-browser focus areas for the year, including work on Core Web Vitals, the View Transitions API, WebAssembly, and Layout.

Baseline conversations and community content

Rachel Andrew of Chrome Developer Relations joined Brian Rinaldi at TheJam.dev for a fireside chat covering Interop and Baseline. The conversation, including audience Q&A, explains why Baseline exists and how it helps developers gauge web platform availability without compatibility anxiety.

CSS-Tricks' Geoff Graham published a piece on the baseline-status WordPress plugin, which wraps the Baseline Status web component for easier embedding in pages. The component renders current Baseline information for a given feature, and CSS-Tricks has adopted it across their site—for instance, on their documentation page for the @scope rule.

RUMvision, which integrated Baseline into its RUM solution last month, has now published a case study detailing how they built that integration. It's a useful look at bringing Baseline awareness into real-world performance tooling.

Popover API Baseline date corrected

The Popover API was originally marked Baseline Newly available in April 2024. A serious bug in one browser engine's implementation went unnoticed at the time, meaning the API was flagged too early. The Baseline Newly available date has now been updated to January 27, 2025. Chrome Developer Relations previously explained the reasoning behind the correction.

Talks and tooling updates

Mariko Kosaka spoke at HalfStack Conference in Phoenix about interoperability beyond mere availability—defining what it means for features to work across all device types, and how Baseline simplifies that assessment. No video is available yet, but her slide deck has been published.

ESLint has officially added CSS linting support. The announcement includes the require-baseline rule, which enforces the use of Baseline features in project CSS—another sign of Baseline support spreading through the developer tooling ecosystem.