Writing your first server action

A server action is a function that only ever runs on the server but can be called from the client. It replaces the route handler you would otherwise write by hand.

What this lesson covers

• Define an action and call it from a form or an event
• Revalidate the affected data after a write
• Keep write credentials on the server side of the call

This lesson sits in Server Actions and Mutations, part of Next.js App Router in Depth. It assumes what came before it and leads directly into the next lesson in the module.