Microsoft Edge and Interop 2026

Microsoft Edge remains steadfast in its commitment to enhancing the web platform, striving for a more powerful, predictable, and reliable experience. A key avenue for achieving these objectives is through active participation in the Interop project, now entering its sixth year. This initiative sees collaboration with industry giants such as Mozilla, Igalia, Google, and Apple, all working towards a more interoperable web.

This year, the Interop project has received an impressive array of proposals for inclusion in Interop 2026. The insights gathered from these submissions reveal critical areas where inconsistent behaviors hinder site performance, slow down developers, and stifle the adoption of innovative features. Feedback from the developer community underscores the importance of addressing these interoperability challenges, and Microsoft Edge has championed the inclusion of as many relevant proposals as possible into the Interop framework.

Launching Interop 2026

Today marks a significant milestone as we unveil the focus areas agreed upon by Interop members for 2026. By aligning our engineering efforts on these shared priorities, we aim to maximize our impact:

• attr(): Expanding the CSS attr() function to allow any property to read HTML attributes of any type and unit.
• contrast-color(): Enhancing color tooling across the web.
• Container style queries: Enabling styling elements based on the properties of their container elements.
• Custom highlights: Allowing the styling of arbitrary text ranges without altering the DOM.
• Dialogs and popovers: Improving the interoperability of the element and popover API.
• Fetch: Enhancing the fetch() API to support streaming request bodies and more.
• IndexedDB: Boosting performance for reading large datasets with the getAllRecords() method.
• JSPI for Wasm: Integrating WebAssembly with JavaScript promises.
• Media pseudo-classes: Implementing pseudo-classes like :playing, :paused, and :buffering for audio/video element states across browsers.
• Navigation API: Continuing to enhance interoperability, including support for navigation pre-commit handlers.
• Scoped custom element registry: Allowing multiple custom element registries to coexist safely.
• Scroll-driven animations: Creating advanced animations based on user scroll position.
• Scroll snap: Improving consistency in CSS scroll snapping behavior.
• shape(): Adding interoperable support for the shape() CSS function to define complex shapes around elements.
• View Transitions: Enhancing same-document behavior and implementing cross-page transitions.
• Web compat: Addressing real-world compatibility issues.
• WebRTC: Continuing to improve WebRTC interoperability and resolve outstanding issues.
• WebTransport: Advancing support for the WebTransport API for low-latency, bidirectional communication over HTTP/3.

In addition to these focus areas, Interop members are also dedicated to advancing several investigation efforts:

• Accessibility testing: Streamlining the process for testing web feature accessibility.
• JPEG XL: Developing a comprehensive test suite, paving the way for JPEG XL to potentially become a focus area in future iterations.
• Mobile testing: Enhancing infrastructure for testing mobile-specific features.
• WebVTT: Continuing to refine the specification and test suite for this feature, opening the door for future inclusion in the Interop project.

For further details on these focus areas and investigation efforts, interested parties can refer to the full descriptions available on the Interop GitHub repository. The Interop 2026 dashboard will serve as a valuable resource for tracking progress throughout the year.

Advocating for more

The Microsoft Edge team remains attuned to the needs of developers, recognizing that numerous long-standing interoperability issues persist. To monitor advancements on the most impactful, enduring challenges, a supplementary Top Developer Needs dashboard has been launched. In previous years, initiatives like Custom Highlights and scroll-driven animations have benefited from this focus, shaping Interop priorities. A refresh of the dashboard is anticipated in the coming weeks.

Moreover, the team is committed to pushing the boundaries of web capabilities by introducing new features, which will inform future iterations of the Interop project. Advocacy for increased transparency within the Interop group remains a priority, as developers have expressed concerns regarding the opacity of the focus area selection process. The team agrees that enhanced visibility into how priorities are established is essential.

Closing Interop 2025

The previous year saw the Interop 2025 project make significant strides across various domains, many of which originated in Chromium before evolving into standards and being implemented across different browsers. Key achievements include:

• CSS anchor positioning: Unlocking reliable cross-browser positioning for tooltips and other anchored UI patterns.
• View Transitions: Enabling smoother app-like transitions on the web, including across pages.
• Navigation API: Simplifying the implementation of stateful, single-page-app experiences.
• Core Web Vitals: Aligning browsers on essential performance metrics that reflect user experience quality.
• JSON module scripts: Streamlining data loading in modern JavaScript.
• 
  

  element: Creating accessible disclosure widgets.

For more insights, the Interop 2025 dashboard is available for review. All participating browsers conclude the Interop 2025 project with an impressive score of at least 98%. The anticipation for the enhancements that Interop 2026 will bring is palpable, and gratitude is extended to the community for their invaluable proposals and feedback. These contributions, alongside surveys and other developer signals, play a crucial role in identifying priorities and areas for improvement within the web ecosystem.