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Getting Started with FastAPI

FastAPI is a modern, fast (high-performance) web framework for building APIs with Python 3.7+ based on standard Python type hints.

Installation

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pip install fastapi
pip install "uvicorn[standard]"

Basic Example

Here's a simple FastAPI application:

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from fastapi import FastAPI

app = FastAPI()

@app.get("/")
async def root():
    return {"message": "Hello World"}

@app.get("/items/{item_id}")
async def read_item(item_id: int):
    return {"item_id": item_id}

Running the Application

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uvicorn main:app --reload

Key Features

  • Fast: Very high performance, on par with NodeJS and Go
  • Fast to code: Increase the speed to develop features by about 200% to 300%
  • Fewer bugs: Reduce about 40% of human-induced errors
  • Intuitive: Great editor support. Completion everywhere. Less time debugging
  • Easy: Designed to be easy to use and learn. Less time reading docs
  • Short: Minimize code duplication. Multiple features from each parameter declaration
  • Robust: Get production-ready code. With automatic interactive documentation
  • Standards-based: Based on (and fully compatible with) OpenAPI and JSON Schema

Next Steps