What is a REST API and what does a frontend developer do with it?

REST is a style of building HTTP APIs where you model resources (users, posts, settings) and use standard methods like GET, POST, PUT/PATCH, and DELETE. Front-end code usually calls these endpoints with fetch, sends JSON, reads JSON, and maps responses to UI state, loading spinners, and error handling. Status codes and headers matter as much as the response body.

const res = await fetch('/api/cart', { headers: { Accept: 'application/json' } });
if (!res.ok) throw new Error('Cart failed to load');
const data = await res.json();

Start simple: try this concept in a tiny project before moving to advanced tools.