Practice real frameworks

Hands-on React exercises that mirror real engineering work — from core fundamentals to the patterns interviewers actually probe. Every challenge is graded automatically and mapped to a skill below.

React is a JavaScript library for building user interfaces, particularly single-page applications where data changes over time. It uses a component-based architecture, allowing developers to build encapsulated components that manage their own state. React's virtual DOM efficiently updates and renders components as data changes, optimizing performance. It is often used with TypeScript for type safety and improved developer experience.