Ultra fast asyncio event loop.



uvloop is a fast, drop-in replacement of the built-in asyncio event loop. uvloop is implemented in Cython and uses libuv under the hood.

The project documentation can be found here. Please also check out the wiki.


uvloop makes asyncio 2-4x faster.


The above chart shows the performance of an echo server with different message sizes. The sockets benchmark uses loop.sock_recv() and loop.sock_sendall() methods; the streams benchmark uses asyncio high-level streams, created by the asyncio.start_server() function; and the protocol benchmark uses loop.create_server() with a simple echo protocol. Read more about uvloop in a blog post about it.


uvloop requires Python 3.5 or greater and is available on PyPI. Use pip to install it:

$ pip install uvloop

Using uvloop

To make asyncio use uvloop, you can install the uvloop event loop policy:

import asyncio
import uvloop


or, starting with uvloop 0.12:

import uvloop


Building From Source

To build uvloop, you'll need Python 3.5 or greater:

  1. Clone the repository:

    $ git clone --recursive git@github.com:MagicStack/uvloop.git
    $ cd uvloop
  2. Create a virtual environment and activate it, for example:

    $ python3.7 -m venv uvloop-dev
    $ source uvloop-dev/bin/activate
  3. Install development dependencies:

    $ pip install -r requirements.dev.txt
  4. Build and run tests:

    $ make && make test


uvloop is dual-licensed under MIT and Apache 2.0 licenses.