FAQ

Does it only work with FastAPI?

No. The name says FastAPI because that is where the gap is most obvious, but nothing depends on FastAPI. Any Python project with models works, and app / lifespan work with any ASGI 3 app: Starlette, Litestar, Quart, Django's ASGI handler and others.

Is it safe to have in production images?

It is a development tool, like IPython. Keep it in a dev dependency group. If you do need a shell on a server, installing it there is no different from installing IPython: it does nothing until you run it.

Does it change my database?

Only when you do. fastapi-repl opens a session and never commits. The one exception is opt-in: Tortoise's generate_schemas = true creates missing tables.

Does starting the shell run my app?

Importing app runs your module-level code, just like uvicorn would. The lifespan (startup and shutdown) only runs with lifespan = true or --lifespan. No server is started and no port is opened.

Why is my session not an async with block?

The shell creates the session for you and closes it when you exit, so you can use it across prompts. If you prefer your own, turn it off (session = false) and use your session factory as normal.

Can I use a different ORM?

Yes: write an adapter. It is usually 30 to 60 lines. Without an adapter, imports, objects and hooks already let you load anything.

How is this different from python -i or IPython.embed()?

Those give you a prompt. fastapi-repl gives you a prompt with your project loaded and a working async setup, and cleans up after itself. It is the difference between python -i manage.py and manage.py shell_plus.

Which Python versions are supported?

Python 3.11 and newer.