aiohttp

aiohttp is an asynchronous HTTP client/server framework for Python built on top of asyncio. It enables writing asynchronous web clients and servers using coroutines and is suitable for high-concurrency I/O-bound applications.

On the server side, the aiohttp.web package provides a full-featured web framework with routing, request handlers, middleware, signals, static file serving, templates, and WebSocket support. It emphasizes non-blocking I/O and streaming, including streaming responses and request payloads. The typical usage is to create an Application, register routes, add middleware, and run the app via web.run_app.

On the client side, the aiohttp.ClientSession class offers an asynchronous HTTP client capable of making requests, handling cookies, redirects, compression, streaming bodies, and connection pooling. It integrates with asyncio for asynchronous execution and is suitable for API clients, scrapers, or microservices.

Features and ecosystem: aiohttp supports WebSockets, asynchronous file handling, and session management. It ships with utilities for routing and common async programming patterns, and can be extended with templates and other integrations. The project is released under the Apache License 2.0 and is widely used in the Python community.

Use considerations: Because it relies on asyncio, it is best suited for I/O-bound workloads rather than CPU-bound tasks. It requires Python 3.7 or newer. aiohttp is not a traditional WSGI framework and is designed for asynchronous applications that run within the asyncio event loop.