The Gunicorn "Green Unicorn" (pronounced jee-unicorn or gun-i-corn)[2] is a PythonWeb Server Gateway Interface (WSGI) HTTP server. It is a pre-fork worker model, ported from Ruby'sUnicorn project. The Gunicorn server is broadly compatible with a number of web frameworks, simply implemented, light on server resources and fairly fast.[3] It is often paired with Nginx, as the two have complementary features.[4]