How to setup simple flask application

MATHIVATHANA S — Sat, 29 Mar 2025 12:17:32 +0000

What is flask?
Flask is one of the lightweight framework of python, which is based on web application,(i.e) can build web applications using python with flask application.

Create a folder of your choice
Create file name app.py
Insert the below code

from flask import Flask  // importing Flask class from flask 
app = Flask(__name__)   //

@app.route('/') //decorator tells Flask what URL should trigger our function.
def hello_world():
    return 'Hello, World!'

if __name__ == "__main__":
    app.run(debug=True)  // starts flask dev. server with debug mode to log errors.

open the root folder of app.py eg: flask_app/
run this on terminal

pip install flask
python app.py

open browser, navigate to http://127.0.0.1:5000/ , you will see output Hello, World! [due to technical difficulties could not able to attach the screenshot]

DEV Community: MATHIVATHANA S

How to setup simple flask application