Entries are now open for , a yearly effort where anyone, from users to web developers, can submit their best ideas to improve cross-browser interoperability. Here’s how to participate.

Interop , when Apple, Bocoup, Google, Italia, Microsoft, and Mozilla came together “to commit to improve interoperability in 15 key areas that will have the most impact on web developer experience.”

The project, which stemmed from Google’s initiative, gained enough traction to become an annual event.

As the group explains it:

“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.”

Apple stresses that it is important that any submitted idea is built on top of a mature web standard from the likes of W3C, and TC39, otherwise “it’s too early for it to be a Focus Area for Interop 2026.”

The company notes that testability is also an essential criteria, so it is important to keep these two things in mind.

The Interop group has published an extensive documentation on , where they also flesh out the criteria outlined above.

But in a nutshell, as explained on Apple’s WebKit blog:

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 for that technology. Like .)
• Tested: Look up and link to coverage. If more tests are needed, how can they be created this fall?

Apple also says that aside from reading , participants can either , or comment on “to help further make the case.”

Proposal submissions , September 4, and will run through September 24.