--- title: Safari 27 brings top-level await and WebAssembly JSPI to... description: Safari 27 completes cross-browser support for two long-awaited web platform features. Top-level await, part of ES2022, now works across all major browsers... canonical: https://daily.dev/posts/safari-27-brings-top-level-await-and-webassembly-jspi-to-all-browsers-ajkb9qiuh twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Safari 27 brings top-level await and WebAssembly JSPI to all browsers | daily.dev og:description: Safari 27 completes cross-browser support for two long-awaited web platform features. Top-level await, part of ES2022, now works across all major browsers... og:url: https://daily.dev/posts/safari-27-brings-top-level-await-and-webassembly-jspi-to-all-browsers-ajkb9qiuh og:image: https://api.daily.dev/og/posts/aJkB9QIuh.png og:image:alt: Safari 27 brings top-level await and WebAssembly JSPI to all browsers 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. # Safari 27 brings top-level await and WebAssembly JSPI to all browsers **[Collections](https://daily.dev/sources/collections)** · 2 min read · 2 upvotes · 0 comments ## Summary Safari 27 completes cross-browser support for two long-awaited web platform features. Top-level await, part of ES2022, now works across all major browsers after uneven support made it unreliable to use. JSPI (JavaScript Promise Integration) for WebAssembly also lands, letting synchronous native code suspend on an async Promise. Vercel's Guillermo Rauch noted that libfx already uses JSPI to make fetch calls from native WebAssembly code, which matters more as logic increasingly moves into WebAssembly. ## Content Safari 27 is out, and it's one of the bigger releases in recent memory - the release notes grew from 58 to 83 features since the June beta, alongside 844 bug fixes. Here's what's worth paying attention to: ## Built-in MCP server Safari now ships a native MCP (Model Context Protocol) server, letting coding agents like Claude Code and Codex control the browser directly. That means inspecting the DOM, watching network requests, taking screenshots, and reading console output - all without browser extensions or manual setup. It's a meaningful shift in how AI-assisted development can interact with a live browser environment. ## Top-level await, finally cross-browser Safari 27 ships a rewritten ES module loader that properly supports top-level await. This is ES2022 syntax, and with this release it works consistently across all major browsers. It's been a long time coming. ## WebAssembly JSPI JSPI (JavaScript Promise Integration) lets synchronous native code suspend on an async Promise. In practice, this means WebAssembly modules can use browser APIs like `fetch` without requiring the surrounding code to be rewritten as async. As more logic moves into native/Wasm layers, this kind of interop matters a lot. ## CSS and layout - **Scroll Anchoring** - stops the page from jumping when content loads above the viewport - **Customizable Select** - native `