React Server Actions: Patterns, Pitfalls, and Production Use

Server Actions shipped into React's stable model with a lot of promise: colocate mutation logic with your components, skip the boilerplate API route, get progressive enhancement for free. In practice, teams are hitting real problems — validation gaps, mixed client/server state, and actions that grow into unmaintainable blobs. Here's a grounded look at where they shine and where you need guardrails.

A Server Action is an async function marked with "use server" that executes on the server but can be called from the client — including from form action props. The browser sends a POST request under the hood; React handles serialization.