Server Actions

Server Actions are an alpha feature in Next.js, built on top of React Actions. They enable server-side data mutations, reduced client-side JavaScript, and progressively enhanced forms. They can be defined inside Server Components and/or called from Client Components:

Actions are an experimental feature in React, allowing you to run async code in response to a user interaction.

Actions are not Next.js or React Server Components specific, however, they are not yet available in the stable version of React. When using Actions through Next.js, you are opting into using the React experimental channel.

Actions are defined through the action prop on an element. Typically when building HTML forms, you pass a URL to the action prop. With Actions, React now allows you to pass a function directly.

React also provides built-in solutions for optimistic updates with Actions. It's important to note new patterns are still being developed and new APIs may still be added.