Flask is a small, friendly framework for building web apps with Python. It is the opposite of the big, batteries-included frameworks: Flask gives you the essentials — routing, requests, and templates — and lets you choose everything else. If you know a little Python and want to turn it into a real website, Flask is the shortest and clearest path.

How does Flask work? You create an app, define routes, and run a development server. A route is a simple rule: when someone visits / , run this function and return a page. Your pages are templates written in HTML with small placeholders, so a function can pass data — like a list of books — into a page that displays it. Forms send data back to your routes, and extensions add databases, login, and anything else you need, only when you need it. The whole framework fits in your head, which is exactly the point.

Flask is a good fit for beginners because you can have a working website in under ten lines of code.…