--- title: Interop 2027 is now accepting proposals | daily.dev description: The Interop initiative is now accepting proposals for its 2027 round, targeting web platform features that behave inconsistently across browsers. The... canonical: https://daily.dev/posts/interop-2027-is-now-accepting-proposals-c764s2c0g twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Interop 2027 is now accepting proposals | daily.dev og:description: The Interop initiative is now accepting proposals for its 2027 round, targeting web platform features that behave inconsistently across browsers. The... og:url: https://daily.dev/posts/interop-2027-is-now-accepting-proposals-c764s2c0g og:image: https://api.daily.dev/og/posts/c764s2C0G.png og:image:alt: Interop 2027 is now accepting proposals og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Interop 2027 is now accepting proposals **[Collections](https://daily.dev/sources/collections)** · 3 min read · 2 upvotes · 0 comments ## Summary The Interop initiative is now accepting proposals for its 2027 round, targeting web platform features that behave inconsistently across browsers. The submission window is September 3 to September 23, 2026, with proposals filed as GitHub issues. Strong proposals target features backed by mature standards (W3C specs, TC39 proposals) and can be validated through Web Platform Tests; features lacking test coverage can instead be proposed as an Interop Investigation to build groundwork before formal testing. ## Content ## What is Interop? Interop is an annual initiative where browser vendors and web developers agree on a set of focus areas to improve cross-browser interoperability. Each year, the group picks existing web platform features that work inconsistently across browsers and commits to closing those gaps. Past cycles have covered things like container queries, the `:has()` selector, and CSS grid improvements. ## The 2027 call for proposals Submissions opened September 3, 2026 and close September 23, 2026. Proposals are filed as GitHub issues. To be eligible, a feature needs a mature web standard behind it - W3C, TC39, or similar - and enough coverage in the Web Platform Tests suite to be measurable. If a feature you care about lacks sufficient tests, you can still submit it as an **Interop Investigation** rather than a full focus area proposal. The guidance on writing a strong proposal comes down to five things: - **Specific** - target a well-defined feature or behavior, not a broad category - **Impactful** - explain who is affected and how often - **Valuable** - make the case for why interoperability matters here specifically - **Stable** - the spec should be settled enough that browsers can implement against it - **Tested** - link to relevant WPT tests and standards documents If a proposal already exists that covers your idea, the organizers prefer collaboration on that issue over filing a duplicate. Developers can also vote on existing proposals through the Developer Signals site. ## One developer's wishlist Rick Viscomi (taking over from Jake Archibald's earlier experiment) is running a community voting initiative alongside the official process. One developer published their ranked top ten, which gives a decent sense of what's on people's minds: 1. **Custom CSS functions and mixins** - the kind of thing Sass has handled for years, finally coming to native CSS 2. **`margin-trim`** - removes unwanted margins at the edges of containers; this one's been on the list before 3. **Non-round `border-radius` shapes** - squircles and similar superellipse curves that designers have wanted forever 4. **Customizable native `