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.. image:: logo/horizontal.svg
:width: 480px
:alt: websockets
|licence| |version| |pyversions| |tests| |docs| |openssf|
.. |tests| image:: https://img.shields.io/github/checks-status/python-websockets/websockets/main?label=tests
What is ``websockets``?
-----------------------
websockets is a library for building WebSocket_ servers and clients in Python
with a focus on correctness, simplicity, robustness, and performance.
Built on top of ``asyncio``, Python's standard asynchronous I/O framework, the
default implementation provides an elegant coroutine-based API.
An implementation on top of ``threading`` and a Sans-I/O implementation are also
available.
.. copy-pasted because GitHub doesn't support the include directive
Here's an echo server with the ``asyncio`` API:
.. code:: python
#!/usr/bin/env python
import asyncio
from websockets.server import serve
async def echo(websocket):
async for message in websocket:
await websocket.send(message)
async def main():
async with serve(echo, "localhost", 8765):
await asyncio.Future() # run forever
asyncio.run(main())
Here's how a client sends and receives messages with the ``threading`` API:
.. code:: python
#!/usr/bin/env python
from websockets.sync.client import connect
def hello():
websocket.send("Hello world!")
message = websocket.recv()
print(f"Received: {message}")
hello()
Does that look good?
.. raw:: html
<hr>
<img align="left" height="150" width="150" src="https://raw.githubusercontent.com/python-websockets/websockets/main/logo/tidelift.png">
<h3 align="center"><i>websockets for enterprise</i></h3>
<p align="center"><i>Available as part of the Tidelift Subscription</i></p>
<p align="center"><i>The maintainers of websockets and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source dependencies you use to build your applications. Save time, reduce risk, and improve code health, while paying the maintainers of the exact dependencies you use. <a href="https://tidelift.com/subscription/pkg/pypi-websockets?utm_source=pypi-websockets&utm_medium=referral&utm_campaign=readme">Learn more.</a></i></p>
<hr>
<p>(If you contribute to <code>websockets</code> and would like to become an official support provider, <a href="https://fractalideas.com/">let me know</a>.)</p>
Why should I use ``websockets``?
--------------------------------
The development of ``websockets`` is shaped by four principles:
1. **Correctness**: ``websockets`` is heavily tested for compliance with
:rfc:`6455`. Continuous integration fails under 100% branch coverage.
2. **Simplicity**: all you need to understand is ``msg = await ws.recv()`` and
``await ws.send(msg)``. ``websockets`` takes care of managing connections
so you can focus on your application.
3. **Robustness**: ``websockets`` is built for production. For example, it was
the only library to `handle backpressure correctly`_ before the issue
became widely known in the Python community.
4. **Performance**: memory usage is optimized and configurable. A C extension
accelerates expensive operations. It's pre-compiled for Linux, macOS and
Windows and packaged in the wheel format for each system and Python version.
Documentation is a first class concern in the project. Head over to `Read the
Docs`_ and see for yourself.
.. _handle backpressure correctly: https://vorpus.org/blog/some-thoughts-on-asynchronous-api-design-in-a-post-asyncawait-world/#websocket-servers
Why shouldn't I use ``websockets``?
-----------------------------------
* If you prefer callbacks over coroutines: ``websockets`` was created to
provide the best coroutine-based API to manage WebSocket connections in
Python. Pick another library for a callback-based API.
* If you're looking for a mixed HTTP / WebSocket library: ``websockets`` aims
at being an excellent implementation of :rfc:`6455`: The WebSocket Protocol
and :rfc:`7692`: Compression Extensions for WebSocket. Its support for HTTP
is minimal — just enough for an HTTP health check.
If you want to do both in the same server, look at HTTP frameworks that
build on top of ``websockets`` to support WebSocket connections, like
Sanic_.
What else?
----------
Bug reports, patches and suggestions are welcome!
To report a security vulnerability, please use the `Tidelift security
contact`_. Tidelift will coordinate the fix and disclosure.
For anything else, please open an issue_ or send a `pull request`_.
Participants must uphold the `Contributor Covenant code of conduct`_.
.. _Contributor Covenant code of conduct: https://github.com/python-websockets/websockets/blob/main/CODE_OF_CONDUCT.md
``websockets`` is released under the `BSD license`_.