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This release adds Python 3.10 support, updates bundled libuv to 1.42.0
and fixes a handful of issues.


* Python 3.10 support (#432)
  (by @elprans in 2519e2d for #432)

* Bump vendored libuv to 1.42.0 (#433)
  (by @elprans in a62f781 for #433)

* Use cibuildwheel to build wheels (#435)
  (by @elprans in 20febe0 for #435)

* Add support for <timer handle>.when()
  (by Jens Jorgensen in 62b2af9)


* Fix ref issue when protocol is in Cython
  (by @fantix in 70cafc8 for #2222)

* set python_requires
  (by @graingert in c808a66)

* SSL: schedule first data after waiter wakeup
  (by @fantix in 2081db8)

* Fix a possible race condition in sslproto test
  (by @fantix in b0526cd for #412)

* Fix `call_soon_threadsafe` thread safety
  (by @fantix in 4b803b1)

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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 3.7 or greater and is available on PyPI. Use pip to install it:

$ pip install uvloop

Note that it is highly recommended to upgrade pip before installing uvloop with:

$ pip install -U pip

Using uvloop

Call uvloop.install() before calling or manually creating an asyncio event loop:

import asyncio
import uvloop

async def main():
    # Main entry-point.


Building From Source

To build uvloop, you'll need Python 3.7 or greater:

  1. Clone the repository:

    $ git clone --recursive
    $ cd uvloop
  2. Create a virtual environment and activate it:

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

    $ pip install -e .[dev]
  4. Build and run tests:

    $ make
    $ make test


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