Next.js Mutations & Server Actions, In Depth
An expert guide to changing data in the Next.js App Router with Server Actions and TypeScript — what a Server Action is and how 'use server' works, form actions and progressive enhancement, useActionState for form state and validation errors, useFormStatus for pending UI, useOptimistic for optimistic updates, revalidating and redirecting after a mutation, binding extra arguments, calling actions outside forms, and the security rules that matter because actions are public endpoints — with common mistakes and exercises.