tRPC -- Skill Router

Decision Tree

What are you trying to do?

Define a tRPC backend (server)

• Initialize tRPC, define routers, procedures, context, export AppRouter -> Load skill: server-setup
• Add middleware (.use), auth guards, logging, base procedures -> Load skill: middlewares
• Add input/output validation with Zod or other libraries -> Load skill: validators
• Throw typed errors, format errors for clients, global error handling -> Load skill: error-handling
• Call procedures from server code, write integration tests -> Load skill: server-side-calls
• Set Cache-Control headers on query responses (CDN, browser caching) -> Load skill: caching
• Accept FormData, File, Blob, or binary uploads in mutations -> Load skill: non-json-content-types
• Set up real-time subscriptions (SSE or WebSocket) -> Load skill: subscriptions

Host the tRPC API (adapters)

• Node.js built-in HTTP server (simplest, local dev) -> Load skill: adapter-standalone
• Express middleware -> Load skill: adapter-express
• Fastify plugin -> Load skill: adapter-fastify
• AWS Lambda (API Gateway v1/v2, Function URLs) -> Load skill: adapter-aws-lambda
• Fetch API / Edge (Cloudflare Workers, Deno, Vercel Edge, Astro, Remix) -> Load skill: adapter-fetch

Consume the tRPC API (client)

• Create a vanilla TypeScript client, configure links, headers, types -> Load skill: client-setup
• Configure link chain (batching, streaming, splitting, WebSocket, SSE) -> Load skill: links
• Use SuperJSON transformer for Date, Map, Set, BigInt -> Load skill: superjson

Use tRPC with a framework

• React with TanStack Query (useQuery, useMutation, queryOptions) -> Load skill: react-query-setup
• Next.js App Router (RSC, server components, HydrateClient) -> Load skill: nextjs-app-router
• Next.js Pages Router (withTRPC, SSR, SSG helpers) -> Load skill: nextjs-pages-router

Advanced patterns

• Generate OpenAPI spec, REST client from tRPC router -> Load skill: openapi
• Multi-service gateway, custom routing links, SOA -> Load skill: service-oriented-architecture
• Auth middleware + client headers + subscription auth -> Load skill: auth

Quick Reference: Minimal Working App

// server/trpc.ts
import { initTRPC } from '@trpc/server';

const t = initTRPC.create();

export const router = t.router;
export const publicProcedure = t.procedure;

// server/appRouter.ts
import { z } from 'zod';
import { publicProcedure, router } from './trpc';

export const appRouter = router({
  hello: publicProcedure
    .input(z.object({ name: z.string() }))
    .query(({ input }) => ({ greeting: `Hello ${input.name}` })),
});

export type AppRouter = typeof appRouter;

// server/index.ts
import { createHTTPServer } from '@trpc/server/adapters/standalone';
import { appRouter } from './appRouter';

const server = createHTTPServer({ router: appRouter });
server.listen(3000);

// client/index.ts
import { createTRPCClient, httpBatchLink } from '@trpc/client';
import type { AppRouter } from '../server/appRouter';

const trpc = createTRPCClient<AppRouter>({
  links: [httpBatchLink({ url: 'http://localhost:3000' })],
});

const result = await trpc.hello.query({ name: 'World' });

See Also

• server-setup -- full server initialization details
• client-setup -- full client configuration
• adapter-standalone -- simplest adapter for getting started
• react-query-setup -- React integration
• nextjs-app-router -- Next.js App Router integration