Gunicorn ‘Green Unicorn’ is a Python WSGI HTTP Server for UNIX. It’s a pre-fork worker model. The Gunicorn server is broadly compatible with various web frameworks, simply implemented, light on server resources, and fairly speedy.

Installation

Here’s a quick rundown on how to get started with Gunicorn. For more details read the documentation.

$ pip install gunicorn
  $ cat myapp.py
    def app(environ, start_response):
        data = b"Hello, World!\n"
        start_response("200 OK", [
            ("Content-Type", "text/plain"),
            ("Content-Length", str(len(data)))
        ])
        return iter([data])
  $ gunicorn -w 4 myapp:app
  [2014-09-10 10:22:28 +0000] [30869] [INFO] Listening at: http://127.0.0.1:8000 (30869)
  [2014-09-10 10:22:28 +0000] [30869] [INFO] Using worker: sync
  [2014-09-10 10:22:28 +0000] [30874] [INFO] Booting worker with pid: 30874
  [2014-09-10 10:22:28 +0000] [30875] [INFO] Booting worker with pid: 30875
  [2014-09-10 10:22:28 +0000] [30876] [INFO] Booting worker with pid: 30876
  [2014-09-10 10:22:28 +0000] [30877] [INFO] Booting worker with pid: 30877