Simon Willison’s Weblog

Subscribe

15th February 2026 - Link Blog

Launching Interop 2026. Jake Archibald reports on Interop 2026, the initiative between Apple, Google, Igalia, Microsoft, and Mozilla to collaborate on ensuring a targeted set of web platform features reach cross-browser parity over the course of the year.

I hadn't realized how influential and successful the Interop series has been. It started back in 2021 as Compat 2021 before being rebranded to Interop in 2022.

The dashboards for each year can be seen here, and they demonstrate how wildly effective the program has been: 2021, 2022, 2023, 2024, 2025, 2026.

Here's the progress chart for 2025, which shows every browser vendor racing towards a 95%+ score by the end of the year:

Line chart showing Interop 2025 browser compatibility scores over the year (Jan–Dec) for Chrome, Edge, Firefox, Safari, and Interop. Y-axis ranges from 0% to 100%. Chrome (yellow) and Edge (green) lead, starting around 80% and reaching near 100% by Dec. Firefox (orange) starts around 48% and climbs to ~98%. Safari (blue) starts around 45% and reaches ~96%. The Interop line (dark green/black) starts lowest around 29% and rises to ~95% by Dec. All browsers converge near 95–100% by year's end.

The feature I'm most excited about in 2026 is Cross-document View Transitions, building on the successful 2025 target of Same-Document View Transitions. This will provide fancy SPA-style transitions between pages on websites with no JavaScript at all.

As a keen WebAssembly tinkerer I'm also intrigued by this one:

JavaScript Promise Integration for Wasm allows WebAssembly to asynchronously 'suspend', waiting on the result of an external promise. This simplifies the compilation of languages like C/C++ which expect APIs to run synchronously.

Posted 15th February 2026 at 4:33 am

Recent articles

This is a link post by Simon Willison, posted on 15th February 2026.

Monthly briefing

Sponsor me for $10/month and get a curated email digest of the month's most important LLM developments.

Pay me to send you less!

Sponsor & subscribe