FastAPI leverages Starlette and Pydantic to deliver high-performance Web API development in Python. Its asynchronous support and automatic data validaiton make it suitable for modern microservices architectures.

Environment Configuration

Install the core framework using the package manager:

pip install fastapi

An ASGI server is required to handle requests. Uvicorn is commonly paired with FastAPI:

pip install uvicorn

Implementing Endpoints

Create a module named server.py. Initialize the applicasion instance and define routes using decorators. The example below sets up a status checker and a data retrieval endpoint.

from fastapi import FastAPI

application = FastAPI()

@application.get("/health")
async def check_status():
    return {"status": "operational", "service": "api-gateway"}

@application.get("/resources")
async def list_resources():
    return {"count": 0, "items": []}

The decorator maps HTTP methods and paths to asynchronous functions. Response dictionaries are automatically converted to JSON.

Launching the Server

Execute the following command in the project directory to start the development server. The --reload flag ensures changes to server.py trigger an automatic restart.

uvicorn server:application --reload

The service becomes availabel at http://127.0.0.1:8000. Specific endpoints respond at /health and /resources.

Automated Documentation

Interactive documentation is generated automatically. Two standard interfaces are provided:

• http://127.0.0.1:8000/docs (Swagger UI)
• http://127.0.0.1:8000/redoc (ReDoc)

These tools enable direct testing of API endpoints and visualization of request schemas.