Async IO in Python: Trio vs. Asyncio

Mar 25, 2024 ยท 2 min read

Python developers have two main options for asynchronous I/O concurrency - asyncio and Trio. Both allow you to write non-blocking, concurrent code in Python. But which one is better for your use case?

How They Work

Fundamentally, asyncio and Trio work very similarly:

import asyncio

async def main():
    await asyncio.sleep(1)
import trio

async def main():
    await trio.sleep(1) 

They both provide an event loop and async/await syntax to allow non-blocking calls.

Key Differences

Some key differences:

  • Readability - Trio aims to be simpler and easier to reason about. Its API is more consistent.
  • Error Handling - Trio has more structured error handling through its Cancelled and MultiError abstractions.
  • Support - Asyncio is older and more widely supported. It ships with Python. Trio must be installed separately.
  • Performance - For I/O heavy workloads, Trio benchmarks faster in many scenarios.
  • Use Cases

    Asyncio makes sense if you need integration with a library that doesn't support Trio, or you want something that comes built-in to Python.

    Trio is a good choice for newer applications that are I/O bound. Its design addresses pain points from asyncio.

    Key Takeaways

  • Both Trio and asyncio enable concurrency in Python.
  • Trio offers better readability and error handling where asyncio has wider usage and support.
  • For I/O bound workloads, Trio can provide better performance.
  • Choose based on your specific needs - or try them both!

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