FastAPI

What is FastAPI?

FastAPI is a modern, fast (high-performance) web framework for building APIs with Python, based on standard Python type hints. It is one of the fastest Python frameworks available — on par with NodeJS and Go.

Why FastAPI?

• Speed — Based on Starlette and Pydantic. Benchmarks show performance close to NodeJS and Go.
• Fast to code — Type hints mean your IDE can autocomplete everything. Fewer bugs.
• Automatic docs — Go to /docs for interactive Swagger UI. Go to /redoc for ReDoc. Both auto-generated from your code.
• Validation — Request body, query parameters, path parameters are all validated automatically via Pydantic.
• Async — Native support for async def endpoints.

Getting Started

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def read_root():
    return {"Hello": "World"}

@app.get("/items/{item_id}")
def read_item(item_id: int, q: str | None = None):
    return {"item_id": item_id, "q": q}

uvicorn main:app --reload

FastAPI for ML Serving

FastAPI is the de facto standard for serving machine learning models as APIs. Load your model once on startup, serve predictions via a POST endpoint. Works seamlessly with PyTorch, TensorFlow, scikit-learn, and HuggingFace.