What is React

The most widely used tool for building the screens of a website. Written in JavaScript or TypeScript, and released by Facebook.

In plain terms

React builds an interface out of small reusable pieces called components. It is the default choice for web frontends and the largest single framework job market. A React developer writes JavaScript or TypeScript every day. Vue and Svelte solve the same problem with the same core ideas.

What it tells you about a developer

React depth is mainstream frontend competence with the industry-standard tool. Strong React developers work in Vue or Svelte within weeks. Next.js or Node.js alongside it marks them as full-stack.