Your First Flask App

What is Flask?

Flask is a lightweight Python web framework. It lets you build websites and APIs quickly with minimal setup.

Installation

Make sure you have Python installed, then run the following in your terminal.

pip install flask

Creating the App

Create a file called app.py and add the following code.

from flask import Flask

app = Flask(__name__)

@app.route("/")

def home():

return "Hello, Flask!"

if __name__ == "__main__":

app.run(debug=True)

Running the App

In your terminal, run the following command.

python app.py

Then open your browser and visit http://127.0.0.1:5000 to see your app running.

Adding More Routes

You can add as many routes as you need.

@app.route("/about")

def about():

return "This is the about page."

Using Templates

Instead of returning plain text, render HTML templates using render_template.

from flask import render_template

@app.route("/")

def home():

return render_template("index.html")

Next Steps

Learn how to pass data to templates, handle forms, and connect a database.