React 19 — The Guide

Everything you need to know about new primitives, the Actions model, Server Components, the compiler, form handling, optimistic updates, and the complete architectural shift of React version 19.

JSX in React 19 — The Complete Reference

Everything you need to know about JSX — how it compiles, every expression pattern, conditional rendering, lists, fragments, refs, context, error boundaries, and every React 19 addition.