Published: September 4, 2025
It's been seven months since Interop 2025 kicked off. Work on the focus areas for this year continues, but with an eye to the future, today we're opening proposals for Interop 2026. From today through September 24, 2025 the feature submission form is open. Submit your ideas for features to become part of the Interop 2026 effort. As in previous years we expect to see a large number of feature submissions, and all will be considered through this process.
What makes a good proposal?
The Interop project aims to take things that have already been through the standards process, and make them interoperable. Therefore, the first thing to consider is whether your idea has a stable specification, and no outstanding objections from one or more browser vendors. Past features have typically been implemented in at least one browser before becoming part of the project.
Features that have a stable implementation should also have the other thing that's needed for a successful proposal—a good test suite. The success of a feature in the project is based on browsers passing these tests, so we need to know that there are enough tests in the first place.
Find out more information by reading the Proposal Guide. This guide includes some additional signals that can help to boost the chances of your proposal succeeding.
Interop 2025 progress
For inspiration, take a look at the Interop 2025 focus areas. When we started the project in February, the scores for each browser were as follows.
Our post at the start of the project shared some of the features we were most excited about. For example, same-document view transitions which are now in Firefox Nightly as an Experimental feature.
That post also described additions to the
<details>
element—such as the
::details-content
pseudo-element which shipped in Safari 18.4. In the same version Safari also
landed the sideways writing mode values, bringing that feature to Baseline Newly
available.
The ongoing beta of Safari
26
promises support for
overflow-block
and
overflow-inline.
These logical properties were also included in Chrome 135 and will become
Baseline Newly available when Safari 26 ships to stable. This beta also includes
CSS anchor positioning, and many other features and fixes to improve the Safari
Interop score.
In addition, mutation events have now been removed from all browsers.
You can see the improvements on the Interop 2025 dashboard, and we still have a number of browser releases to go before the end of the year.
We're excited to see more improvements to the web platform, and more features becoming Baseline Newly available through Interop 2026—get your proposals in today!