| FastAPI | zapline |
|---|
@app.get("/items/{id}") | #[get("/items/{id}")] |
def read(id: int, q: str | None = None) | async fn read(Path(id): Path<i64>, Query(q): Query<Params>) |
| Pydantic model | #[model] struct (derives serde, JsonSchema and Validate) |
| Automatic 422 validation errors | Valid<Json<T>> → 422 with per-field details |
/docs, /openapi.json | App::openapi(OpenApi::new("API", "1.0")) |
Depends(get_db) | Dep<T>, State<T>, custom extractors, Cached<T> |
BackgroundTasks | BackgroundTasks |
HTTPException(404) | Err(Error::not_found()) |
TestClient(app) | app.test() |
uvicorn --reload | zapline dev |
| Lifespan events | on_startup / on_shutdown |
| Concept | zapline |
|---|
| Controllers | Modules of #[get]/#[post] handlers mounted with .mount((...)), or Routes groups |
| Beans and services, constructor injection | App::provide, App::provide_dyn::<dyn Trait>, async provide_with factories, the Dep<T> extractor |
application.yml profiles | Config::load(): config/default.toml + config/{profile}.toml + APP__* env vars + .env |
| Filters, interceptors | Middleware: App::wrap (pre-routing), App::wrap_route / Routes::wrap (post-routing) |
Guards, @PreAuthorize | .require_roles([...]), .require_scopes([...]), Guard |
| Actuator (health, metrics) | Health and Metrics plugins |
@Scheduled | App::schedule(Schedule::every(..), job) |
| Exception handlers | App::error_handler |
| Modules / starters | Plugins |
zapline will feel familiar. Extractors, IntoResponse and State work the same way. The differences:
App::run(addr) gives you a tuned thread-per-core server, with no #[tokio::main] and no serve glue.- There's no tower
Service/Layer stack. Middleware is async fn(Request, Next) -> Response.
- State is keyed by type, so you can register many types and the router has no
S generic parameter.
- OpenAPI, validation, DI, configuration, auth, sessions, metrics and health checks are built in.
- Route macros look the same (
#[get("/")]), and they also document the route in OpenAPI.
- Handlers and state are
Send, so any Tokio-ecosystem library works.
- Both use thread-per-core runtimes. zapline uses
SO_REUSEPORT listeners and hyper's HTTP stack.