It’s that exciting time of year again when we start considering Interop proposals for next year! We’re thrilled to invite you to help shape the future of web interoperability.

Interop 2027 is just around the corner, and we want your ideas to make the web platform even more awesome. Whether you’re a seasoned pro or a newcomer with fresh perspectives, we want to hear from you.

Key Dates to Remember

• Proposal Submission Opens: September 3, 2026
• Submission Deadline: September 23, 2026

Don’t miss this opportunity to influence the direction of web standards and browser implementations.

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. 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 want a new CSS feature to exist, 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 piece should work get determined and written down.

If you want 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 the 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 existing 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 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 fixing this 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 ideas. 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.