Sanic — Async Python Web Framework Built for Speed

What it is

Sanic is an asynchronous Python web framework built from the ground up with async/await support. It provides HTTP/1.1 and HTTP/2, WebSocket support, streaming responses, middleware, blueprints for modular routing, and auto-generated OpenAPI documentation. Sanic runs its own async event loop, eliminating the need for external ASGI servers in most deployments.

Sanic targets Python developers building high-performance APIs, microservices, and real-time applications. Its async-first design makes it suitable for I/O-bound workloads like API gateways, proxy services, and applications with many concurrent connections.

How it saves time or tokens

Sanic's built-in server means no separate ASGI/WSGI configuration. You define routes with decorators, add middleware, and run the server in one file. The auto-generated OpenAPI docs eliminate the need to maintain API documentation manually. Blueprints let you organize large applications into modular components without boilerplate.

How to use

1. Install Sanic with pip install sanic.
2. Define your application with route decorators and async handler functions.
3. Run the server with sanic app:app or by calling app.run() in your script.

Example

from sanic import Sanic, json

app = Sanic('MyAPI')

@app.get('/api/items')
async def list_items(request):
    return json([{'id': 1, 'name': 'Widget'}])

@app.post('/api/items')
async def create_item(request):
    return json(request.json, status=201)

@app.websocket('/ws')
async def feed(request, ws):
    while True:
        data = await ws.recv()
        await ws.send(f'Echo: {data}')

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=8000)

Related on TokRepo

• API Tools — API frameworks and integration tools
• Coding AI Tools — Developer productivity tools

Common pitfalls

• Sanic is async-only. Blocking calls (synchronous database queries, file I/O without aiofiles) will block the event loop and degrade performance. Use async libraries for all I/O operations.
• Sanic runs its own server and manages worker processes internally. This differs from frameworks like Flask or FastAPI that rely on Uvicorn or Gunicorn. Check the Sanic deployment docs for production configuration.
• Sanic's ecosystem is smaller than Flask or FastAPI. Some third-party extensions may not have Sanic equivalents. Verify library compatibility before committing.