Interop 2026 is a groundbreaking cross-browser initiative led by Apple, Google, Igalia, Microsoft, and Mozilla, aimed at enhancing web compatibility and feature consistency across leading browsers. Following the significant success of Interop 2025 in raising compatibility scores from 25 to 95 and introducing features like View Transitions and CSS Anchor Positioning, Interop 2026 sets its sights on 20 targeted areas of improvement.
The new initiative continues the collaborative spirit of its predecessor, drawing from developer feedback to prioritize the development of modern web features. These include innovations such as cross-document View Transitions, scroll-driven animations, WebTransport, and CSS container style queries. In addition, ongoing efforts to enhance reliability involve refining existing functionalities like CSS scroll snap, the Navigation API, and WebRTC.
Interop 2026 also delves into four key investigation areas: enhancing accessibility testing, building a more robust mobile testing infrastructure, exploring JPEG XL for advanced imaging, and improving WebVTT for video subtitles. This extensive scope underscores the project’s commitment to making web development more consistent and reliable across diverse platforms.
Progress is meticulously tracked through a public dashboard that leverages automated tests to ensure alignment with web standards. This holistic approach seeks to eliminate time-consuming compatibility issues for developers, fostering a more harmonious web development landscape.
In summary, with 15 new focus areas and five carryovers from previous projects, Interop 2026 channels the collective expertise of top browser manufacturers to drive innovation and reduce fragmentation in web technologies. Features already shipping in browsers like Safari—such as contrast-color(), media pseudo-classes, and scoped custom element registries—illustrate the tangible advancements being achieved through this initiative.

Collections

Interop 2026 is a collaborative initiative by Apple, Google, Igalia, Microsoft, and Mozilla to improve web compatibility across browsers. Building on Interop 2025's success (raising compatibility scores from 25% to 95%), the new project targets 20 areas including cross-document View Transitions, scroll-driven animations, WebTransport, CSS container style queries, and improvements to CSS scroll snap, Navigation API, and WebRTC. Four investigation areas focus on accessibility testing, mobile testing infrastructure, JPEG XL support, and WebVTT enhancements. Progress is tracked via a public dashboard using automated tests, with features like contrast-color() and scoped custom element registries already shipping in browsers like Safari.

Introducing Interop 2026: Advancing Web Compatibility