Why do we need Gunicorn?

Now the problem is a python web application cannot be deployed on traditional web servers such as Apache because they are designed to serve static web pages created using HTML and CSS. Python web applications are more complex than static web pages, so you need a WSGI server like Gunicorn specifically intended for Python web applications and frameworks. If your application contains static content, you can usually use a server such as Nginx to serve the static content. An image demonstration will help to understand the role of a Gunicorn server more clearly.

As you see in the image above, Gunicorn is designed to work with web servers and Python web applications to perform the following tasks:

• How to communicate with a number of web several responding to lots of web requests at once and distributing the load.
• keeping up multiple processes of the web application running.

Some more features of Gunicorn:

• Gunicorn server is surprisingly well suited with python web frameworks like Django and Flask, Falcon, etc. 
• It is mild on server resources and pretty rapid performance. 
• It is often used with NGINX as a proxy in production environments.

Gunicorn `Green Unicorn` is a pure Python HTTP server for WSGI applications, originally published by Benoit Chesneau on 20th February 2010. It’s a WSGI (Web Server Gateway Interface) HTTP server, a calling convention used for a group of web servers that forward requests to web applications or frameworks written in Python. So, in a nutshell, it’s an intermediary/interface between the web server and your python application.