FastAPI 0.115 Cheatsheet

Getting started

• Create a virtual environment — Create an isolated environment for the project's packages.
• Activate the virtual environment — Use the environment's Python and packages in this shell. On Windows run .venv\Scripts\activate.
• Install FastAPI — Install FastAPI with the standard extras: the fastapi command, Uvicorn and the other common dependencies.

Running the app

• Start the development server — Run the app with auto-reload. It listens on 127.0.0.1:8000 by default.
• Change the host and port — Listen on all interfaces on port 8080, for example inside a container or on a LAN.
• Start the production server — Run without auto-reload, listening on 0.0.0.0 by default.
• Run several worker processes — Start multiple processes to use more than one CPU core.
• Run with Uvicorn directly — Start the app object named app in main.py with auto-reload.
• Fetch the OpenAPI schema — Download the JSON schema FastAPI generates. The interactive docs are served at /docs.

Testing

• Install the test tools — TestClient needs httpx, and pytest runs the tests.
• Run the tests — Run every test under the current directory.
• Run one test — Run a single test function and show print output.

Deployment

• Record the installed packages — Write the exact package versions to a requirements file for deployment.
• Build a Docker image — Build an image from the Dockerfile in the current directory.
• Run the Docker image — Start a container in the background and publish port 80.

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