Deno 2.9

Deno 2.9 is here, headlined by deno desktop, a new way to build native desktop applications from the web stack you already know, with no Electron boilerplate and a single binary at the end. It s also the easiest release yet to bring an existing Node project over: deno install now reads npm, pnpm, yarn, and Bun lockfiles directly, so switching your package manager to Deno takes a couple of commands, not a migration. There s plenty more below, from CSS module imports and a much stronger test runner to faster startup and Node.js 26 compatibility. To upgrade to Deno 2.9, run the following in your terminal: deno upgradeIf Deno is not yet installed, run one of the following commands to install or learn how to install it here. # Using Shell (macOS and Linux): curl -fsSL https://deno.land/install.sh | sh # Using PowerShell (Windows): iwr https://deno.land/install.ps1 -useb | iexdeno desktop Building a desktop app has usually meant pulling in Electron or Tauri, wiring up a separate toolchain, and shipping a bundle that bears little resemblance to the rest of your project. Deno 2.9 introduces deno desktop. Point it at a script (or a web framework project) and it produces a native, self-contained desktop application where the UI runs in a webview, your logic runs in Deno, and the whole thing compiles down to a single distributable binary (#33441). deno desktop is experimental in 2.9. The surface described here is stabilizing and some platform features are still landing. The simplest app is an entrypoint that serves your UI. Deno.serve() inside a desktop entrypoint automatically binds to the port the webview opens, so there s no port wiring to do: Deno.serve(() => new Response( " Hello from Deno desktop 👋 ", { headers: { "content-type": "text/html" } }, ) );$ deno desktop main.tsThat opens a native window rendering your page. deno desktop shares the same framework detection as deno compile: run it with no entrypoint (or deno desktop .) and it auto-detects the web framework in the current directory (Next.js, Astro, Fresh, Remix, Nuxt, SvelteKit, SolidStart, TanStack Start, and Vite SSR are all supported), builds it, and wraps the result: $ deno desktop # auto-detect the framework in the current directory $ deno desktop --hmr # run with Hot Module Replacement during developmentNative desktop APIs Richer apps get a full set of native desktop APIs built right into the runtime under Deno.*, available immediately with no extra dependencies. Deno.BrowserWindow gives you programmatic control over window size, position, visibility, menus, and DevTools, and lets you bridge between the webview and Deno: bind a function in the entrypoint with window.bind() and call it from page JavaScript via the bindings namespace. There s also Deno.Tray for system-tray icons and panels, and Deno.Dock on macOS: const tray = new Deno.Tray(); tray.setIcon(iconBytes); const panel = tray.attachPanel({ url: "https://localhost:8000/panel" }); panel.window.bind("doThing", async () => {/* ... */});prompt(), alert(), and confirm() render as native dialogs, and Deno.autoUpdate() wires up a polling auto-updater that applies binary patches in the background. Webview or CEF Every desktop app needs a browser engine to draw its UI, and deno desktop ships two, selected with --backend: $ deno desktop main.ts # native webview (default) $ deno desktop --backend cef main.ts # bundled ChromiumMost apps are happiest on the default webview; reach for cef when you need a guaranteed-identical engine on every platform. Distribution Because deno desktop is built on the same machinery as deno compile, the output is a standalone binary with your code and assets embedded. The format follows the extension you pass to --output: .app and .dmg on macOS, .exe or an .msi installer on Windows, and .AppImage, .deb, or .rpm on Linux. You don t need a fleet of machines to ship cross-platform, though. --target cross-compiles the app to any supported platform and --all-targets builds them all in one command, so a single Linux CI runner (or your laptop) can turn out binaries for Windows, macOS, and Linux together. The Windows .msi and Linux .deb / .rpm installers are authored in pure Rust, so they re produced from any host with no platform-specific packaging toolchain: $ deno desktop --output MyApp.dmg main.ts # build for the host $ deno desktop --target x86_64-pc-windows-msvc main.ts # cross-compile to Windows $ deno desktop --all-targets main.ts # build every supported targetThe five supported targets match deno compile: Linux x64/arm64, Windows x64, and macOS x64/arm64. For smaller artifacts, --compress ships the runtime and UI backend as a self-extracting bundle that unpacks on first launch. For the full guides, see the deno desktop documentation. And for a complete, real-world example, denidian is a note-taking app built with deno desktop: Performance Deno 2.9 ships broad performance gains in startup time, memory use, and HTTP throughput. The De

Deno 2.9

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