How to Run Flask Server on Raspberry Pi: Step-by-Step Guide

To run a Flask server on Raspberry Pi, first install Flask using pip3 install flask. Then create a Python script with your Flask app and run it using python3 your_script.py to start the server accessible on your Pi's IP address.

Syntax

Here is the basic syntax to run a Flask server on Raspberry Pi:

• pip3 install flask: Installs Flask using Python 3's package manager.
• python3 app.py: Runs your Flask application script.
• app.run(host='0.0.0.0', port=5000): Starts the Flask server accessible on all network interfaces at port 5000.

python

from flask import Flask
app = Flask(__name__)

@app.route('/')
def home():
    return "Hello, Raspberry Pi!"

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5000)

Example

This example shows a simple Flask app running on Raspberry Pi that responds with a greeting message when accessed.

python

from flask import Flask
app = Flask(__name__)

@app.route('/')
def home():
    return "Hello, Raspberry Pi!"

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5000)

Output

 * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 123-456-789

Common Pitfalls

Common mistakes when running Flask on Raspberry Pi include:

• Not setting host='0.0.0.0' in app.run(), which makes the server only accessible from localhost.
• Forgetting to install Flask with pip3 for Python 3.
• Running the script with python instead of python3 if Python 3 is required.
• Firewall or network settings blocking port 5000.

python

## Wrong way (server only accessible locally):
# app.run()

## Right way (server accessible on network):
app.run(host='0.0.0.0', port=5000)

Quick Reference

Summary tips for running Flask on Raspberry Pi:

• Use pip3 install flask to install Flask.
• Run your app with python3 app.py.
• Set host='0.0.0.0' in app.run() to allow network access.
• Access the server via http://[Raspberry_Pi_IP]:5000 from other devices.
• Check firewall and network settings if connection fails.

Key Takeaways

Install Flask on Raspberry Pi using pip3 before running your app.

Set host='0.0.0.0' in app.run() to make the server accessible on your network.

Run your Flask app with python3 to ensure Python 3 compatibility.

Access your Flask server from other devices using your Pi's IP and port 5000.

Check network and firewall settings if you cannot connect to the server.