Microsoft’s Edge team has opened the proposal process for Interop 2027, inviting developers, framework authors, and standards communities to submit ideas for improving cross-browser web compatibility. The submission window is open now and remains open through September 23, 2026, with the final scope expected to be published early February 2027.
Here’s everything you need to know about what the project does, what’s in focus this year, and how to get your ideas considered.
What the Interop project actually does
Over the past six years, the Interop project has helped bring key web platform features to a state where developers can rely on them across browsers. Rather than leaving cross-browser compatibility to chance, the effort concentrates on specific technologies and pushes them toward consistent behavior in every major browser.
Technologies that have benefited from this focused work include CSS layout and utilities, View Transitions, anchor positioning, popover, and shadow DOM. In each case, the goal is straightforward: a developer should be able to write a feature once and expect it to work the same way everywhere, without shipping a pile of browser-specific workarounds.
According to the Microsoft Edge Dev blog, the project is guided by input from developers, framework authors, browser vendors, and standards communities — which is exactly why the team is now asking the broader community to help shape next year’s priorities.
What’s in focus for Interop 2027
Browser vendors have continued to work across a broad set of focus areas this year, according to the blog. The current list includes View Transitions, the Navigation API, CSS Anchor Positioning, WebRTC, WebTransport, Dialogs and Popovers, custom highlights, and container style queries, among others.
The underlying premise is that new capabilities are constantly being standardized and implemented, but they only become truly valuable when they work consistently everywhere. Interoperability remains one of the most important challenges facing the web, which is why the project is designed to evolve each year based on the signals it picks up from the people who actually build for it.
What makes a strong proposal
Microsoft laid out five traits that the strongest Interop proposals tend to share. These aren’t just soft guidelines — they’re the criteria the team will use to evaluate submissions against the Interop selection process.
- Solves a real developer problem. Explain how inconsistent browser behavior or missing support actually affects developers in their day-to-day work.
- Has ecosystem impact. Back your case with evidence from developers, frameworks, libraries, issue trackers, surveys, or real-world sites to show the problem is genuinely worth solving.
- Targets standards-based features. Features with a stable specification and broad standards support are stronger candidates than anything still in flux.
- Can be measured. Interop tracks progress using Web Platform Tests (WPT) hosted at wpt.fyi, so proposals should already have strong test coverage or a clear path to adding it.
- Is scoped for meaningful progress. A focused, concrete proposal is easier to evaluate and more likely to succeed than a broad request like “improve CSS” or “fix forms everywhere.”
How to submit your proposal
The submission form is live now at the Interop project’s GitHub page, and Microsoft says to submit even if you’re unsure your idea qualifies. Proposals that don’t get selected still help the team understand where developers are experiencing pain and where future interoperability work is needed.
For anyone who wants to dig deeper before submitting, Microsoft points to the Interop Proposers Guide on GitHub, which walks through the process in more detail.
What this means for you
If you build for the web, your input directly shapes which browser inconsistencies get fixed next year. The Interop team even tracks unselected proposals on its Top Developer Needs dashboard — a page that surfaces the highest-impact, long-running issues developers care about — and it plans to refresh that dashboard early next year. So even a rejected submission can influence longer-term priorities.
For everyday users, the payoff is a web that behaves more consistently across browsers: fewer broken layouts, fewer missing features, and less reliance on browser-specific hacks to make sites work at all.
Where to go from here
Submit your ideas through the GitHub proposal form before the September 23, 2026 deadline, and check the Interop selection process and Proposers Guide pages for full details. The final Interop 2027 scope is scheduled for publication early February 2027.
Source: Windows Blog
Over to you: What web feature has frustrated you most with inconsistent browser behavior — and would you submit it for Interop 2027?
