guv Documentation


The documentation is currently in very active developemnt and not yet complete. Please keep checking back for updates and filing issues for missing sections or suggestions for enhancement.


guv is a fast networking library and WSGI server (like gevent/eventlet) for Python >= 3.2 and pypy3

The event loop backend is pyuv_cffi, which aims to be fully compatible with the pyuv interface. pyuv_cffi is fully supported on CPython and pypy3. libuv >= 1.0.0 is required.

Asynchronous DNS queries are supported via dnspython3. To forcefully disable greendns, set the environment variable GUV_NO_GREENDNS to any value.

guv currently only runs on POSIX-compliant operating systems, but Windows support is not far off and can be added in the near future if there is a demand for this.

This library is actively maintained and has a zero bug policy. Please submit issues and pull requests, and bugs will be fixed immediately.

This project is under active development and any help is appreciated.


Since guv is currently in alpha release state and under active development, it is recommended to pull often and install manually:

git clone
cd guv
python install

Note: libuv >= 1.0.0 is required. This is the first stable version but is a recent release and may not be available in Debian/Ubuntu stable repositories, so you must compile and install manually.

Serve your WSGI app using guv directly

import guv; guv.monkey_patch()
import guv.wsgi

app = <your WSGI app>

if __name__ == '__main__':
    server_sock = guv.listen(('', 8001))
    guv.wsgi.serve(server_sock, app)

Serve your WSGI app using guv with gunicorn

gunicorn -w 4 -b -k guv.GuvWorker wsgi_app:app

Note: you can use wrk to benchmark the performance of guv.

Crawl the web: efficiently make multiple “simultaneous” requests

import guv; guv.monkey_patch()
import requests

def get_url(url):
    return requests.get(url)

def main():
    urls = [''] * 10
    urls += [''] * 10

    pool = guv.GreenPool()
    results = pool.starmap(get_url, zip(urls))

    for i, resp in enumerate(results):
        print('{}: done, length: {}'.format(i, len(resp.text)))

if __name__ == '__main__':


This library makes the following guarantees:

  • Semantic versioning is strictly followed
  • Compatible with Python >= 3.2.0 and PyPy3 >= 2.3.1 (Python 3.2.5)


guv uses the excellent tox and pytest frameworks. To run all tests, run in the project root:

$ pip install pytest
$ py.test