# Compilation and Deployment Targets — Dart

Source: https://www.skillbyai.com/en/dart/p-compile

> Choose between JIT, AOT, JavaScript and WebAssembly outputs.

## Picking the right output

Dart compiles to several targets with **`dart compile`**. **`exe`** produces a self-contained **native executable** with an AOT-compiled snapshot and a small runtime: fast start-up, no Dart SDK needed on the target machine, ideal for CLIs and servers in containers (cross-compilation support for Linux targets has been improving across releases). **`aot-snapshot`** produces a snapshot run with `dartaotruntime`. **`jit-snapshot`** speeds up start-up of JIT-run apps. **`js`** compiles to optimised **JavaScript** for browsers, and **`wasm`** compiles to **WebAssembly** using WasmGC, which Flutter web can also use for better performance in supporting browsers. **`kernel`** produces a portable intermediate format. Flutter's build commands (`flutter build apk`, `ipa`, `web`, `macos`, `windows`, `linux`) use these compilers under the hood. AOT code cannot use `dart:mirrors` (reflection), which is one reason the Dart ecosystem relies on **code generation** rather than run-time reflection for JSON serialisation and dependency injection.

## From source to targets

The same Dart source becomes a native executable, JavaScript or WebAssembly depending on the build command.

![A single source file splitting into three output icons: a terminal window, a JavaScript file and a WebAssembly block.](assets/figures/dart/section-8-map.svg) — Figure 8.1 — dart compile targets.

## Building a small native CLI for a container

AOT executable in a multi-stage image with a minimal runtime base.

```dockerfile
FROM dart:stable AS build
WORKDIR /app
COPY pubspec.* ./
RUN dart pub get
COPY . .
RUN dart compile exe bin/server.dart -o bin/server

FROM scratch
COPY --from=build /runtime/ /
COPY --from=build /app/bin/server /app/bin/server
EXPOSE 8080
CMD ["/app/bin/server"]

# other targets:
# dart compile js   web/main.dart -o build/main.js -O2
# dart compile wasm web/main.dart -o build/main.wasm
```

## No reflection in AOT

Libraries that rely on `dart:mirrors` do not work in Flutter or AOT-compiled code. Prefer packages built on code generation, such as `json_serializable`, `freezed` and `injectable`.

**Quiz:** Which dart compile target produces a self-contained native executable?

- [ ] js
- [ ] kernel
- [x] exe
- [ ] wasm

*Answer:* exe. dart compile exe bundles AOT code with a small runtime into one executable.