fastrs

A FastAPI-equivalent framework for Rust, built as a thin ergonomics layer on top of Axum. It delivers automatic request validation, auto-generated OpenAPI docs, and minimal boilerplate with zero runtime overhead.

Quickstart

use fastrs::{get, post, Json, Path, OpenApi, Created};
use serde::{Deserialize, Serialize};
use validator::Validate;

#[derive(Deserialize, Validate, OpenApi)]
struct CreateUser {
    #[validate(email)]
    email: String,
    #[validate(length(min = 8))]
    password: String,
}

#[derive(Serialize, OpenApi)]
struct UserResponse {
    id: u64,
    email: String,
}

#[post("/users")]
async fn create_user(body: Json<CreateUser>) -> Created<Json<UserResponse>> {
    Created(Json(UserResponse { id: 1, email: body.email.clone() }))
}

#[get("/users/{id}")]
async fn get_user(Path(id): Path<u64>) -> Json<UserResponse> {
    Json(UserResponse { id, email: "x@y.com".into() })
}

fn main() {
    fastrs::App::new()
        .route(create_user)
        .route(get_user)
        .serve_docs_at("/docs")
        .run("0.0.0.0:8000");
}

fastrs vs raw Axum vs FastAPI

Feature	fastrs	Axum	FastAPI
Boilerplate LOC	Minimal (like FastAPI)	High (manual validation/schema)	Minimal
OpenAPI Generation	Compile-time via macros	None natively (3rd party: utoipa)	Runtime via reflection
Request Validation	Automatic, compile-time	Manual inside handler	Automatic
Runtime Overhead	Zero	Zero	High (Python)
Routing Abstraction	Returns raw axum::Router	Native	Custom
Auth Support	Bearer extractor + trait	Manual	OpenAPI auth schemes
Pagination	First-class Page extractor	Manual query parsing	Built-in

Resources

• Full documentation
• crates.io
• Examples
• CHANGELOG