Web framework

A library that handles the plumbing of web requests so you can focus on your app's logic. Flask and Django are examples.

A web framework takes care of the repetitive parts of serving a website — listening for HTTP requests, matching URLs to code, and building responses — so you write only the parts unique to your app. You map a URL to a function, and the framework runs it when a request arrives.

Flask is a small, beginner-friendly Python framework; Django is a larger, batteries-included one. Both let your Python code answer requests with web pages.

Example
# A minimal Flask app
from flask import Flask

app = Flask(__name__)

@app.route("/")          # map a URL to a function
def home():
    return "Hello, world!"

Where this shows up in real Python

Web frameworks (Flask, Django) handle the repetitive parts of serving a site — routing, templates, requests — so you write the interesting bits.

Commonly used Web framework tools

  • @app.route('/') — map a URL to a function
  • render_template('page.html') — fill an HTML template
  • request — read the incoming request
  • return — the response sent back to the browser

Official documentation: Flask Documentation

Related lessons

Related terms