Every year, web developers all over the world get a chance to formally throw their hat in the ring and submit proposals that can impact how the web works in both small and large ways. That time is now. We’re excited to invite you to propose Focus Areas for next year’s Interop Project.

Just like in 2025, 2024, 2023, and 2022, you can submit a proposal of what you believe browser companies should focus on together for Interop 2026. The goal is to fix interoperability bugs in existing features, and ensure new features behave exactly the same in every browser.

What to propose

We’re looking for proposals that address real-world interoperability challenges. If you are struggling to get part of your project to work in every browser at the same time, even while coding with proper progressive enhancement techniques, then you are running into an interoperability challenge.

A lot of interoperability problems have already been addressed in Interop 2025, 2024, 2023, 2022, and 2021. Many long-standing bugs have been fixed. So, what else needs to be tackled? What is truly getting in your way? We want to hear from you, the web developer.

Key dates

• Proposal Submission Opens: September 4, 2025
• Submission Deadline: September 24th, 2025

Essential criteria

There are two essential criteria that all successful Focus Area proposals will have — testability and web standards. If an idea for a needed web technology doesn’t already have a mature web standard (from the W3C, TC39, etc), then it’s too early for it to be a Focus Area for Interop 2026. Those standards are what make it possible to create automated Web Platform Tests, and the test results are what make the Interop Dashboard.

If you have an idea for cool new web technology that should exist, but doesn’t, then look into proposing it (or helping it along) in the appropriate web standards venue. For example, if you have a wish for CSS, check out filing or commenting on an issue at the CSS Working Group. That is where new CSS gets invented, and the details of exactly how every tiny piece should work get determined and written down.

If you wish to propose technology that has insufficient tests or testing infrastructure — consider proposing it as an Interop Investigation. Interop Focus Areas are for web technology that can be tested and scored, while Interop Investigations are assignments the group behind Interop Project gives themselves to encourage improvements for the future.

Writing a great proposal

The best submissions are typically:

• Specific: Identify a specific interoperability issue. One feature (or narrow group of related features) per proposal. Think font-size-adjust, not “typography”.
• Impactful: Provide a clear description of the interoperability problem that needs addressing. Use cases from your own experience are especially helpful.
• Valuable: Explain how web developers and/or users will benefit. Why is this more valuable than other options? Is there evidence this is a common need (perhaps survey results)?
• Stable: Link to the stable web standard that defines the technology you want improved. (Find it on the MDN web doc for that technology. Like here.)
• Tested: Look up and link to WPT test coverage. If more tests are needed, how can they be created this fall? Read the Interop 2026 Proposers Guide to learn more.

Take the time needed to fully make your case! Why is the focus area you are proposing important? If there are hundreds of things that could be considered, why does this one stand out? How does the current state of affairs inhibit web developers? How are users affected? Is this technology something a lot of sites use? How critical is this to be fixed sooner rather than later? And what evidence can you provide that a lot of people share your belief that this is important?

Don’t assume everyone reading the proposals has full knowledge of last year’s proposals, or has had the time to follow all the details of how developers are using (or not using) every web technology out there. Make the case in your proposal. Convince the Interop team!

How to submit

Submit your proposal by filing an issue on Github. Feel free to collaborate with other people.

If someone else has already proposed your idea, use the comments in GitHub issues to help further make the case. (It’s far better to support an existing issue than have two issues for the same or very similar idea.)

You can read proposals submitted in previous years to better understand the process.

Join the Interop Party!

The Interop Project is all about collaboration. By participating, you’re joining a global community of web developers, browser makers, and standards bodies working together to make the web more consistent and reliable across platforms. Share your insights as we make the web even more amazing together. We can’t wait to see your proposals.