Docker + Nginx + Gunicorn + Flask + Let's Encrypt

This repository is a Docker-based boilerplate for deploying a Flask web app with:

• Nginx as a reverse proxy
• Gunicorn as the WSGI server
• Flask for the web application
• Let's Encrypt (Certbot) for free HTTPS and auto renewals
• Docker for easy deployment and reproducibility

Docker Services

Service	Image
app	python:3.13-slim
nginx	nginx:alpine-slim

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Requirements

Dependency	Installation
Docker	Install Docker
Make	sudo apt install make

Other prerequisites:

• A domain or subdomain with a DNS A record pointing to your server's static IP
• Open ports 80 (HTTP) and 443 (HTTPS)

Setup Instructions

1. Get the code on your server

Use curl to download a compressed tarball of the repository from GitHub, so there is no need to install git on the server.

curl -L https://github.com/smallwat3r/docker-nginx-gunicorn-flask-letsencrypt/archive/refs/heads/master.tar.gz | tar -xz
cd docker-nginx-gunicorn-flask-letsencrypt-master

2. Add your user to the Docker group

sudo usermod -aG docker "${USER}" && newgrp docker

3. Configure environment variables

Edit the certbot.env file:

• EMAIL: Email for Certbot (receive alerts)
• DOMAIN: Your domain or subdomain

Also you should check and update (if necessary):

• flask.env for your Flask app environment variables
• src/gunicorn.conf.py for Gunicorn settings

Notes

This is a starter boilerplate, meant to be customized. You’ll likely want to:

• Replace the example app in src/
• Update src/Dockerfile for your dependencies, or slightly change the Gunicorn command required to start your app
• Edit nginx/conf.d/app.conf for your specific reverse proxy needs (e.g., CSP headers)

Running the Application

You may need sudo to run Docker commands depending on your setup.

Start the app

make start

Your app should now be running online with HTTPS!

SSL certificates are automatically renewed weekly.

All available commands

$ make help
Usage: make [TARGET ...]

help            Show this help menu
start           Start docker
start-local     Start docker for local dev (w/o nginx and certbot)
stop            Stop docker
build           (re)build Docker images

License

Licensed under the MIT License.

Support

Have a question or issue?
Open one on the GitHub Issues page

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