Next.js 15 Server Actions: What Changed and Why It Matters
Server Actions in Next.js 15 get stricter typing, better error handling, and deeper RSC integration. Here's how we're using them in production.
Next.js 15 tightens the model for Server Actions: they're now first-class citizens of the React Server Components pipeline. We've moved form submissions and mutations to Server Actions across several client projects and seen cleaner code and fewer round-trips.
**What we use them for** - Form submissions with progressive enhancement - Mutations that invalidate cache or revalidate paths - Internal APIs that don't need a REST endpoint
**Gotchas** - Always validate and sanitize input; don't trust client payloads. - Use `use server` at the top of the file or function. For complex flows, we keep one `actions.ts` per route segment.
We'll follow up with a post on Server Actions + Supabase for auth and data mutations.