Backends

deno desktop runs your app on top of one of several web rendering engines. --backend (or the desktop.backend field in deno.json) selects which engine your app embeds. If you don't choose one, deno desktop uses the WebView backend.

Available backends Jump to heading#

CEF Jump to heading#

deno desktop --backend cef main.ts

Bundled Chromium Embedded Framework. The same engine that powers Chrome, Electron, and Slack. The framework ships inside your .app / app directory under Contents/Frameworks/.

• Identical rendering on macOS, Windows, and Linux.
• Full web platform support, including modern CSS, ES modules, WebGPU, and WebRTC.
• Largest binary size (~150 MB for the framework alone).
• All Deno desktop features supported (DevTools, autoUpdate, tray, dock).

Choose CEF when consistent rendering across platforms matters, or when you need a feature only Chromium ships (e.g. WebGPU on Linux).

WebView (default) Jump to heading#

deno desktop --backend webview main.ts

The operating system's own webview: WKWebView on macOS, WebView2 on Windows, WebKitGTK on Linux.

• Smaller app size (just your code + the backend shim).
• Rendering and feature support varies per platform and OS version.
• Some web features may be missing or behave differently (Web Audio variants, WebGPU availability, etc.).
• DevTools not available (the unified DevTools mux supports CEF only at this time).

Choose WebView when binary size is the primary concern and your UI sticks to broadly-supported web features.

Raw Jump to heading#

{ "desktop": { "backend": "raw" } }

No web engine. Provides window management, input events, clipboard, and the native API surface, but no webview, no Deno.serve() auto-binding, and no bindings.<name>() proxy.

Useful for apps that draw their own UI (WebGPU, Skia, custom rendering) or as a foundation for non-web desktop programs. The raw backend is selected through the desktop.backend field in deno.json; the --backend flag accepts only cef and webview.

Picking a backend Jump to heading#

Switching backends Jump to heading#

Backends are interchangeable for anything except the raw backend: the same app code (windows, bindings, events, navigation, JS execution) works on CEF and WebView without changes.

To switch, change the config or pass the flag:

{ "desktop": { "backend": "webview" } }

deno desktop --backend webview main.ts

The raw backend has no webview, so any APIs that interact with web content (navigation, bindings, executeJs, etc.) are unavailable when using it.

How backends are obtained Jump to heading#

You do not build the rendering backend yourself. The Deno CLI downloads prebuilt backend binaries automatically. Downloads are checksum-verified and cached under <deno_dir>/.

The first build for a new backend / target downloads the archive (a few hundred megabytes for CEF). Subsequent builds use the cache.

Cross-compilation Jump to heading#

--target and --all-targets work with any backend. The CLI downloads the prebuilt backend archive matching the target triple, with no local engine toolchain needed. See Distribution.