aiohttp

Asynchronous HTTP client/server framework for Python.

When to Use aiohttp

Choose aiohttp when:

• Building async Python HTTP servers with fine-grained control over routing and middleware
• Need both client and server in one framework with WebSocket/SSE support
• Streaming responses or large file uploads/downloads are required

Consider alternatives:

• fastapi — When you want automatic OpenAPI docs, Pydantic validation built-in, and simpler syntax
• httpx — When you need a modern async HTTP client with HTTP/2 support (better than aiohttp's)
• Flask/FastAPI + httpx — For sync codebases (aiohttp is purely async)

Quick Start: Minimal Server