Getting started

This guide takes you from pip install py2axum to a binary serving a FastAPI application, using the example in examples/bookshelf: a reading-list API with users, JWT authentication, books, reviews and a WebSocket. Then it shows how to do the same with your own application.

1. Installation: install py2axum and get the examples.
2. First application: generate and build the crate, run the binary, compare it with FastAPI, then do the same with your own application.
3. py2axum check: what translates, route by route, and what to do when something is refused.
4. Hybrid mode: the routes left to a Python process next to the binary.
5. Watch mode: regenerate, rebuild and restart the binary on each change while you port.
6. Migrating an existing application: from uvicorn in production to the binary, step by step, with a switch you can undo.

Deploying the binary (Docker, Kubernetes) is covered in Deployment, its settings in Environment variables.

What you need

• Python ≥ 3.12, at least as recent as the one your application targets: the transpiler parses your code with its own ast module, which only knows its own syntax.
• Rust (stable, via rustup) to compile the generated crate. The first release build takes a few minutes; later builds only recompile your code.
• PostgreSQL: the runtime's database layer targets PostgreSQL (through sqlx).
• An application built on FastAPI, Pydantic v2 and SQLAlchemy 2.0 (async or sync sessions), within the tested version ranges.