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Introduction to FastAPI

FastAPI is a modern, high-performance web framework for building APIs with Python. It is designed to create RESTful APIs quickly, with a focus on performance, ease of use, and automatic generation of interactive API documentation. FastAPI is built on top of Starlette for the web parts and Pydantic for data validation, making it an ideal choice for developing fast and reliable web applications.

Key features of FastAPI include​

  • Fast: As the name suggests, FastAPI is optimized for speed, leveraging asynchronous programming (using Python’s asyncio) to handle requests efficiently. It is one of the fastest Python frameworks available.
  • Easy to Use: FastAPI allows developers to build APIs with minimal code and effort. It automatically generates and validates request data, ensuring high code quality and fewer errors.
  • Automatic Documentation: FastAPI automatically generates interactive OpenAPI and Swagger documentation for your API, making it easy for developers to test and interact with the API.
  • Type Checking and Validation: With FastAPI, you define the data models using Python's type annotations. The framework uses these annotations to validate incoming data automatically, ensuring that the API accepts only correctly formatted data.
  • Asynchronous Support: FastAPI fully supports asynchronous programming, enabling the development of highly concurrent APIs, which can handle many requests simultaneously with minimal latency.

Example​

from fastapi import FastAPI

app = FastAPI()

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

This simple example demonstrates how easy it is to create a basic endpoint using FastAPI. It also automatically provides interactive documentation at /docs using Swagger UI.

Why Choose FastAPI?​

  • Speed: FastAPI is one of the fastest frameworks for Python, comparable to frameworks written in more performant languages like Go and Node.js.
  • Developer-Friendly: Its use of Python's type hints and automatic documentation generation enhances the developer experience by reducing boilerplate code and providing real-time feedback.
  • Production-Ready: It is suitable for building production-quality web services, as it provides robust support for input validation, security features like OAuth2, and asynchronous request handling.