Interop 2026: 20 Focus Areas for a More Compatible Web

Interop 2026, announced on February 13, brings Google, Mozilla, Apple, and Microsoft together around 20 focus areas measured with Web Platform Tests so your pages work the same in every browser. Here is what changes for your code.

What the Interop Project Is and How It's Measured

Interop is a joint initiative by the major browser vendors to make key web platform features behave the same everywhere. It is not a new standard: it is a working agreement. Each year, the teams behind Chrome, Edge, Firefox, and Safari pick platform areas, define tests, and commit to passing them. In 2026 the agreement covers 20 areas, 15 brand new and 5 carried over from Interop 2025.

Web Platform Tests and the Scoreboard Dashboard

Progress is measured with Web Platform Tests (WPT), the automated suite that checks whether a browser meets the standards. The dashboard in February 2026 showed, for example, Chrome Canary at 87 points, Edge Dev at 82, Firefox Nightly at 63, and Safari Technology Preview at 64. Scores climb throughout the year, and the hardest areas concentrate the teams' resources until behavior evens out.

The 20 Focus Areas of 2026

The catalog mixes CSS, low-level APIs, and performance, and several areas were chosen based on the State of HTML and State of CSS surveys: the pain points developers actually report.

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New This Year: Anchor Positioning, Style Queries, and More

CSS Anchor Positioning is one of the stars of the year: it lets you attach one element to another without JavaScript or position calculations, ideal for tooltips and popovers. Style queries extend container queries to the container's style: a component adapts based on a property of its ancestor, not just its size. Custom Highlights rounds out the additions with a way to style text ranges without touching the DOM.

Carryovers from 2025: View Transitions and Scroll Snap

Same-document view transitions reached Baseline thanks to Interop 2025, and the area continues in 2026 to iron out remaining inconsistencies. Scroll snap also returns: subtle differences with mouse and keyboard input are still on the list to eliminate this year.

The Areas That Matter for Your Code

Web Compatibility: ESM and Scroll Event Timing

One of the most interesting additions is a cross-cutting web compatibility area that targets real production problems: edge cases in ES modules, where an import works in one browser and fails in another, and the exact timing of the scroll event, which affects animation and lazy-loading libraries. These are the bugs that never show up in demos but always show up in real applications.

WebTransport: Real HTTP/3

WebTransport receives coordinated attention as the bidirectional API powered by HTTP/3. For multiplayer games, low-latency streaming, or real-time synchronization, it promises to be the modern alternative to WebSockets, and having browsers work together on its consistency is good news for anyone planning to bet on it.

Navigation API and JSPI

The Navigation API lets you intercept history navigations from JavaScript, simplifying single-page apps. JSPI (JavaScript Promise Integration) is the WebAssembly piece: calling synchronous Wasm functions from JavaScript without hand-writing promises, with a direct impact on the performance of apps that port native code.

What This Means for Developers in 2026

Mozilla noted an important nuance: in areas like anchor positioning or the Navigation API, it was possible to score well on the tests and still see inconsistent behavior across browsers. That is why 2026 focuses on real consistency, not just passing tests. The practical takeaway: Interop areas are the ones you can test with confidence and, once they reach Baseline, use in production without looking back.

Conclusion

Interop will not erase browser differences overnight, but it turns compatibility into a measured, shared goal. Keep an eye on the dashboard throughout the year: it is the best way to know which APIs you can adopt now. If you care about the web platform, keep reading the blog for more analysis of CSS, JavaScript, and the features coming to your editor.