docs: document deno compile --engine quickjs

runtime/cli_apps/index.md

@@ -1,5 +1,5 @@
 ---
-last_modified: 2026-06-12
+last_modified: 2026-08-06
 title: "Build CLI apps"
 description: "Build command-line tools with Deno: read arguments and stdin, prompt the user, set exit codes, compile to a single self-contained executable, and distribute your tool."
 ---
@@ -169,6 +169,11 @@ with the usual `--allow-*` flags so it runs without prompting:
 deno compile --output greet greet.ts
 ```
 
+If binary size matters more than raw execution speed, you can build against the
+experimental QuickJS engine instead of V8 with `--engine quickjs`. See
+[choosing a JavaScript engine](/runtime/reference/cli/compile/#choosing-a-javascript-engine)
+for the trade-offs.
+
 ## Embed assets in the binary
 
 A single-file executable should stay single-file even when your tool needs data

runtime/desktop/distribution.md

@@ -1,5 +1,5 @@
 ---
-last_modified: 2026-06-25
+last_modified: 2026-08-06
 title: "Distribution"
 description: "Cross-compile a deno desktop app for macOS, Windows, and Linux from one machine, and produce per-platform output formats: .app, .dmg, .exe directory, AppImage."
 ---
@@ -185,6 +185,13 @@ Cross-compiling from one OS to another requires:
 
 Both downloads are SHA-256 verified and cached under `<deno_dir>/`.
 
+`deno desktop` also accepts `--engine v8|quickjs`, which selects the JavaScript
+engine inside the downloaded runtime library. V8 is the default; the
+experimental QuickJS build is smaller but does not receive the same security
+updates. See
+[choosing a JavaScript engine](/runtime/reference/cli/compile/#choosing-a-javascript-engine)
+for the full trade-offs.
+
 There is **no Rust toolchain involved** in cross-compiling a desktop app. You
 are not compiling Rust on the host; you are downloading prebuilt artifacts for
 the target and packaging them with your code. This is the same model as

runtime/reference/cli/compile.md

@@ -1,5 +1,5 @@
 ---
-last_modified: 2026-06-27
+last_modified: 2026-08-06
 title: "deno compile"
 oldUrl:
   - /runtime/manual/tools/compile/
@@ -106,11 +106,14 @@ Deno supports cross compiling to all targets regardless of the host platform.
 | OS      | Architecture | Target                      |
 | ------- | ------------ | --------------------------- |
 | Windows | x86_64       | `x86_64-pc-windows-msvc`    |
+| Windows | ARM64        | `aarch64-pc-windows-msvc`   |
 | macOS   | x86_64       | `x86_64-apple-darwin`       |
 | macOS   | ARM64        | `aarch64-apple-darwin`      |
 | Linux   | x86_64       | `x86_64-unknown-linux-gnu`  |
 | Linux   | ARM64        | `aarch64-unknown-linux-gnu` |
 
+`aarch64-pc-windows-msvc` (Windows on ARM) is supported starting in Deno 2.9.3.
+
 ## The denort binary
 
 `deno compile` embeds your program into `denort` ("Deno runtime"): a stripped
@@ -128,6 +131,48 @@ To use a custom or locally built runtime as the base, set the `DENORT_BIN`
 environment variable to its path. Deno also picks up a `denort` binary placed
 next to the `deno` executable.
 
+## Choosing a JavaScript engine
+
+:::caution
+
+`--engine quickjs` is experimental and subject to change. It landed after Deno
+2.9.4, so it is available in
+[canary builds](/runtime/reference/cli/upgrade/#canary-build) and in later
+releases.
+
+:::
+
+Compiled binaries run on V8 by default. The `--engine` flag lets you build
+against QuickJS instead, which produces a smaller executable:
+
+```sh
+# Default, same as omitting the flag
+deno compile --engine v8 main.ts
+
+# Build a binary that runs on QuickJS
+deno compile --engine quickjs main.ts
+```
+
+The same flag is available on [`deno desktop`](/runtime/desktop/distribution/),
+where it selects the engine embedded in the app's runtime library.
+
+Trade-offs to weigh before shipping a QuickJS binary:
+
+- **Security updates.** The QuickJS backend does not receive the same security
+  updates as V8. Don't use it for programs that run untrusted input.
+- **Performance.** QuickJS is an interpreter with no JIT, so compute-heavy code
+  runs slower than on V8. Startup and memory use are lower.
+- **Maturity.** The backend is experimental; behavior differences from V8 are
+  possible, so test your program with the engine you intend to ship.
+
+Each engine has its own prebuilt runtime: with `--engine quickjs`, Deno
+downloads `denort-quickjs-<target>.zip` (or `libdenort-quickjs-<target>.zip` for
+`deno desktop`) instead of the default `denort-<target>.zip`. Both variants are
+published for every [supported target](#supported-targets), so cross-compilation
+works the same way. If you override the base runtime with `DENORT_BIN` (or a
+`denort` binary next to `deno`), that binary is used as-is: `--engine` is then
+ignored and Deno prints a warning.
+
 ## Icons
 
 It is possible to add an icon to the executable by using the `--icon` flag when