tiny-flask-docker-image

The smallest possible Flask Docker image — only ~50 MB — for production use.

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📦 Overview

This project aims to create the most lightweight, production-ready Docker image capable of running a Flask app securely and efficiently. It uses a multi-stage build with Alpine Linux and minimal Python dependencies to achieve a tiny footprint.

Goals:

• Ultra-small footprint (~50 MB)
• Secure runtime (minimal unnecessary tools)
• Ease of use (just drop your app.py and requirements.txt)
• Production-grade (run via WSGI server, not Flask dev server)

🚀 Features

• ✅ ~50 MB total image size
• ✅ Based on alpine for ultra-lightweight builds
• ✅ Multi-stage build (builder + final)
• ✅ Production-ready with Gunicorn
• ✅ Stripped binaries & minimal dependencies

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🧱 How it works

The build is split into two stages:

1. Builder stage

   • Uses python:alpine as base
   • Installs dependencies (from requirements.txt)
   • Strips shared object files, removes ensurepip, idlelib, unnecessary modules
   • Produces a lean Python runtime + installed packages

2. Final stage

   • Uses alpine:latest
   • Installs only runtime libraries needed by CPython (BZ2, libffi, SQLite, etc.)
   • Copies in the stripped runtime + installed packages
   • Adds your Flask application (app.py)
   • Runs the app under a WSGI server (Gunicorn) bound to 0.0.0.0:5000

By doing all pip work in the builder and copying the result into the final image, we never need pip or build tools in the runtime container — reducing size and surface area.

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🛠️ Build and Usage

docker build -t tiny-flask .         # ./docker-build.sh
docker run -p 5000:5000 tiny-flask   # ./docker-run.sh

Then open: http://localhost:5000 in your browser

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⚙️ Production Notes

This image uses Gunicorn as a WSGI server instead of Flask’s built-in development server — making it ready for real deployments.

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📜 License

MIT License — feel free to fork, modify, and use.

Copyright© 2025 ArdeshirV, Licensed under MIT