How to Deploy Django to Heroku: Step-by-Step Guide

To deploy a Django app to Heroku, create a Procfile, add gunicorn and dj-database-url to your requirements.txt, configure settings.py for production, then push your code to Heroku using git push heroku main. Heroku will build and run your app automatically.

Syntax

Deploying Django to Heroku involves these key files and commands:

• Procfile: tells Heroku how to run your app.
• requirements.txt: lists Python packages Heroku installs.
• runtime.txt: specifies Python version.
• git push heroku main: deploys your code to Heroku.

Each part ensures Heroku knows how to build and start your Django app.

bash

web: gunicorn your_project_name.wsgi --log-file -

# requirements.txt example
Django>=4.2
gunicorn
dj-database-url
psycopg2-binary

# runtime.txt example
python-3.11.4

Example

This example shows a minimal setup to deploy a Django app named myproject to Heroku.

It includes the Procfile, requirements.txt, and a snippet from settings.py to configure the database.

plaintext

# Procfile
web: gunicorn myproject.wsgi --log-file -

# requirements.txt
Django>=4.2
gunicorn
dj-database-url
psycopg2-binary

# settings.py snippet
import dj_database_url
import os

DATABASES = {
    'default': dj_database_url.config(default='sqlite:///db.sqlite3')
}

# Allow all hosts for Heroku
ALLOWED_HOSTS = ['*']

Output

Heroku builds the app, installs dependencies, and runs gunicorn to serve your Django app on the web.

Common Pitfalls

Common mistakes when deploying Django to Heroku include:

• Not creating a Procfile, so Heroku doesn't know how to start the app.
• Forgetting to add gunicorn to requirements.txt, causing runtime errors.
• Not configuring ALLOWED_HOSTS to include Heroku's domain.
• Missing database configuration with dj-database-url, leading to connection errors.
• Using SQLite in production, which is not supported well on Heroku.

Fix these by adding the missing files, packages, and proper settings.

plaintext

# Wrong Procfile (missing)
# No Procfile means Heroku can't start the app

# Right Procfile
web: gunicorn myproject.wsgi --log-file -

Quick Reference

Summary tips for deploying Django to Heroku:

• Use gunicorn as the web server.
• Create a Procfile with web: gunicorn your_project_name.wsgi --log-file -.
• List all dependencies in requirements.txt.
• Configure DATABASES in settings.py using dj-database-url.
• Set ALLOWED_HOSTS to include your Heroku app domain or use ['*'] for testing.
• Use PostgreSQL add-on on Heroku instead of SQLite.
• Deploy with git push heroku main.

Key Takeaways

Create a Procfile to tell Heroku how to run your Django app with gunicorn.

Add gunicorn and dj-database-url to requirements.txt for proper server and database support.

Configure your settings.py to use dj-database-url for Heroku's PostgreSQL database.

Set ALLOWED_HOSTS correctly to avoid host header errors on Heroku.

Deploy your app by pushing your git repository to Heroku with git push heroku main.