Gunicorn Tutorial – Complete Guide

Welcome to our comprehensive tutorial on “gunicorn”. If you’ve ever delved into the digital world of Python web servers, you’ve likely come across this name. But what is it exactly? Why should it matter to you? And how can learning about it enhance your coding skills? This tutorial will take you on an enlightening journey through the nuts and bolts of gunicorn.

What is Gunicorn?

Gunicorn, short for Green Unicorn, is a Python Web Server Gateway Interface (WSGI) HTTP server. It is a pre-fork worker model, ported from Ruby’s Unicorn server. The Gunicorn server is broadly compatible with a number of web frameworks, simply implemented, light on server resources, and fairly speedy.

Gunicorn acts as an intermediary between your web application and the internet. It allows your application to talk to the outside world by processing incoming requests from the internet and forwarding them to your application. It then receives the responses from your application and transmits them to the internet.

The knowledge of Gunicorn can prove useful in several ways. It’s popular in the Python community due to its resource light and speed qualities. It is a vital component if you plan to serve your Python web applications to the world. Understanding Gunicorn can help you efficiently deploy your web applications and troubleshoot any server issues that might arise.

Besides, learning Gunicorn will bolster your overall web development skills and deepen your understanding of how web servers operate. This is especially helpful if you’re aspiring to become a full-stack Python developer.

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Getting Started with Gunicorn

Before diving into coding, you must ensure that Gunicorn is installed in your work environment. You can do this by using pip, Python’s package manager.

pip install gunicorn

Once Gunicorn is installed, let’s start by running a simple Python WSGI application. Let’s assume you have a basic Flask application (

from flask import Flask
app = Flask(__name__)

def hello_world():
    return 'Hello, World!'

Run the application using Gunicorn as shown below:

gunicorn -w 4 myFlaskapp:app

In the command, -w 4 is used to specify the number of worker processes. This number should generally be between 2-4 worker processes per core in the server.

Configuring Gunicorn

You can also make configurations to Gunicorn using a Python module. This is a more robust method when you need to set multiple settings. Here is a sample file:

workers = 4
bind = ""
max_requests = 5000
timeout = 120

Run Gunicorn with the configuration file path as the argument to the -c option:

gunicorn -c myFlaskapp:app

Working with Gunicorn and Django

Gunicorn can also work seamlessly with Django, another popular Python Framework. Here’s how you can get it up and running:

cd myDjangoproject
gunicorn myDjangoproject.wsgi

This will start the Gunicorn server with Django’s WSGI application.

It’s that simple! With these basics, you can now plug Gunicorn into your Python applications!

Gunicorn Logging

Effective logging can be vital for diagnosing and solving issues related to your web application. Gunicorn provides a robust yet straightforward logging functionality. Here’s how you can set it up in your Python module:

errorlog = "-"

accesslog = "-"

The “-” key denotes that the errors and access logs will be directed to stderr and stdout respectively. If you want to specify a file instead, simply replace “-” with the file path.

Running Gunicorn as a Daemon

Sometimes, you might want to run your Gunicorn server in the background. This is known as running Gunicorn as a daemon. Here is an example:

gunicorn myFlaskapp:app --daemon

In this case, the –daemon flag is used to run Gunicorn in the background.

Running Gunicorn with SSL

SSL is a security protocol for establishing encrypted links between a web server and a browser. You can run Gunicorn with SSL using the following command:

gunicorn --certfile=server.crt --keyfile=server.key myFlaskapp:app

Here, server.crt and server.key are your SSL certificate and private key respectively.

Reload the Gunicorn Server

Gunicorn provides functionality to reload the server without losing any pending connections. Here is how you do it:

kill -HUP masterpid

Where masterpid is the PID of Gunicorn’s master process. This command sends a SIGHUP to Gunicorn, causing it to gracefully restart.

Stop the Gunicorn Server

To stop the Gunicorn server, use the following command:

kill masterpid

This command will kill the Gunicorn master process, thus stopping the server.

By mastering the use of Gunicorn, you can ensure that your Python web applications run smoothly and efficiently. Its ease of use, wide compatibility with many Python frameworks, and lightweight process make it an excellent choice for deploying Python web applications.

Where to Go Next

Now that you have grasped the basics of using Gunicorn, it’s time to keep the wheel of learning in motion. The beauty of the coding world is that there’s always something new and exciting to learn. And the good news is, you don’t have to look far for your next learning adventure.

We invite you to explore our Python Mini-Degree – a comprehensive collection of courses that teach Python programming. Python is lauded for its simplicity, readability, and versatility, making it a great choice for beginners and seasoned developers alike.

Our Python Mini-Degree covers an array of topics, from coding basics and algorithms to game and app development. The curriculum includes hands-on projects that you can add to your portfolio and practical knowledge application sessions for a comprehensive learning experience.

Whether you’re an aspiring coder or a seasoned developer looking to diversify your skillset, our Python courses are designed to meet your individual learning needs. Our courses are detailed, flexible, and you can access them anytime, anywhere.


In conclusion, mastering the use of Gunicorn can significantly enhance your efficiency as a Python web developer. It is an invaluable tool that, coupled with your determination and creativity, can lead you to create outstanding work and significantly contribute to the digital world.

At Zenva, we are committed to helping you on your learning path. Feel free to explore our Python Mini-Degree for a comprehensive Python learning experience. Remember, the journey of a thousand miles begins with a single step. Continue stepping forward in your coding journey with us!

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