trpc

Create a fetchRequestHandler in app/api/trpc/[trpc]/route.ts exporting GET and POST handlers, then wrap your root layout with a client provider containing trpc.Provider and QueryClientProvider. Server components can call procedures directly via createCaller with a context object.

Queries are read operations sent via GET, cached by React Query, and idempotent. Mutations are write operations sent via POST, not cached, and used for database writes or side effects like sending emails.

Choose tRPC for full-stack TypeScript monorepos where you control both client and server. Use REST for public language-agnostic APIs, and GraphQL for complex data graphs with multiple client types. tRPC is not suitable for non-TypeScript consumers.

Create an isAuthed middleware that checks ctx.session and throws a TRPCError with UNAUTHORIZED code when missing. Build a protectedProcedure with t.procedure.use(isAuthed) so ctx.user is guaranteed and type-narrowed in all protected routes.

Yes, tRPC supports subscriptions over WebSockets using wsLink on the client and applyWSSHandler on the server. Procedures return observables that emit events, consumed in React via the useSubscription hook.

Avoid tRPC for public APIs consumed by non-TypeScript clients, polyglot microservices, or mobile apps in Swift/Kotlin. It also lacks OpenAPI documentation generation, making REST or GraphQL better for external developer platforms.