Highly concurrent networking library

c10k, concurrency, greenlet, network, production-ready, python
pip install eventlet==0.34.3



New usages of eventlet are now heavily discouraged! Please read the following.

Eventlet was created almost 18 years ago, at a time where async features were absent from the CPython stdlib. With time eventlet evolved and CPython too, but since several years the maintenance activity of eventlet decreased leading to a growing gap between eventlet and the CPython implementation.

This gap is now too high and can lead you to unexpected side effects and bugs in your applications.

Eventlet now follows a new maintenance policy. Only maintenance for stability and bug fixing will be provided. No new features will be accepted, except those related to the asyncio migration. Usages in new projects are discouraged. Our goal is to plan the retirement of eventlet and to give you ways to move away from eventlet.

If you are looking for a library to manage async network programming, and if you do not yet use eventlet, then, we encourage you to use asyncio, which is the official async library of the CPython stdlib.

If you already use eventlet, we hope to enable migration to asyncio for some use cases; see Migrating off of Eventlet. Only new features related to the migration solution will be accepted.

If you have questions concerning maintenance goals or concerning the migration do not hesitate to open a new issue, we will be happy to answer them.




Eventlet is a concurrent networking library for Python that allows you to change how you run your code, not how you write it.

It uses epoll or libevent for highly scalable non-blocking I/O. Coroutines ensure that the developer uses a blocking style of programming that is similar to threading, but provide the benefits of non-blocking I/O. The event dispatch is implicit, which means you can easily use Eventlet from the Python interpreter, or as a small part of a larger application.

It's easy to get started using Eventlet, and easy to convert existing applications to use it. Start off by looking at the examples, common design patterns, and the list of basic API primitives.

Getting Eventlet

The easiest way to get Eventlet is to use pip:

pip install -U eventlet

To install latest development version once:

pip install -U https://github.com/eventlet/eventlet/archive/master.zip

Building the Docs Locally

To build a complete set of HTML documentation:

tox -e docs

The built html files can be found in doc/build/html afterward.

Supported Python versions

Python 3.7-3.12 are currently supported.