>_DevLog
ReactFrameworks

React 19: New Features Overview

2026-02-28

React 19 introduces Actions, the use() API, improved hydration error messages, and native document metadata support. Here's a practical rundown.

Actions

Actions simplify async state transitions in forms and event handlers. Instead of managing isPending and error state manually, the useActionState hook handles it:

import { useActionState } from 'react'

async function submitForm(prevState: State, formData: FormData) {
  const result = await saveData(formData)
  return result
}

function MyForm() {
  const [state, action, isPending] = useActionState(submitForm, initialState)

  return (
    <form action={action}>
      <button disabled={isPending}>Save</button>
    </form>
  )
}

The use() API

use() reads a Promise or Context inside render — including inside conditions and loops:

function UserCard({ userPromise }: { userPromise: Promise<User> }) {
  const user = use(userPromise)
  return <p>{user.name}</p>
}

Wrap with <Suspense> to handle the loading state.

Native Document Metadata

Return <title>, <meta>, and <link> tags directly from any component — React hoists them to <head> automatically:

function PostPage({ post }: { post: Post }) {
  return (
    <>
      <title>{post.title}</title>
      <meta name="description" content={post.summary} />
      <article>{post.content}</article>
    </>
  )
}

Improved Hydration Errors

React 19 now shows a diff of the server vs client HTML mismatch in the console, making hydration errors dramatically easier to debug.

React 19 is a substantial release that reduces boilerplate in async data flows while keeping the core mental model intact.