Type-Safe Route URL Generator for FastAPI

Stop guessing route names. This tool analyzes your FastAPI application and generates a typed wrapper for url_path_for, giving you instant autocompletion and catching typos before they hit production.

Here's an example project which uses it (checkout just py_generate)

Installation

uv add generate-fastapi-typed-routes --dev

Usage

Point the tool at your FastAPI app and tell it where to save the generated code:

generate-fastapi-typed-routes --app-module myapp.main:app --output myapp/routes.py

Note that since this tool needs to import an app modules you cannot run it via uvx, which runs outside of your venv.

Now, instead of using the raw app.url_path_for, import your generated function:

from myapp.routes import app_url_path_for

# Complete with IDE autocompletion and type checking!
url = app_url_path_for("get_user_profile", user_id=123)

CLI Arguments

• --app-module: The import path to your FastAPI app instance (e.g., src.main:app). You can pass this multiple times to generate helpers for multiple apps in one file.
• --output: The file path where the generated Python code will be saved.
• --prefix: (Optional) Custom prefix for the generated function. Defaults to the app variable name (e.g., app becomes app_url_path_for). Use this if you have multiple apps to keep things distinct.
• --directory / -d: (Optional) The directory containing the application module (default: current directory). Use this if your app is not in the current working directory.

Features

• Zero Runtime Overhead: The generated code is just type hints and a simple wrapper.
• IDE Autocompletion: Never type a route name manually again. Your editor will list every available route name defined in your app.
• Refactoring Safe: Change a route name in your app, and your type checker (mypy, pyright) will flag every place usage that needs updating.
• Multi-App Support: Easily manage routes for projects with multiple FastAPI instances.

MIT License

This project was created from iloveitaly/python-package-template