Is Flask front end or backend?

In web development, there is only one “front end” language, and that’s JavaScript (and things compiled to JavaScript, like TypeScript). Everything else runs on a server somewhere, not in the browser, and that makes it “back end”. Flask, which is written in Python, is back end .

Let’s look at the small, yet powerful JavaScript UI library ReactJS in action, as we build a basic web application. This app is powered by Python 3 and the Flask framework in the back-end and React in the front.

Project directory