tRPC Patterns — T3 Turbo / v11 / App Router

Expert reference for tRPC v11 with Next.js App Router, React Query, TypeScript, and Drizzle. API lives in packages/api/src/. Canonical pattern: queryOptions() / mutationOptions(), never direct hooks.

Router Composition

// packages/api/src/router/user.ts
export const userRouter = createTRPCRouter({
  getById: protectedProcedure
    .input(z.object({ id: z.string() }))
    // illustrative only; ctx.db is BLOCKED here — see § DB Import — ctx.db is BLOCKED
    .query(({ ctx, input }) => ctx.db.query.user.findFirst({ where: eq(users.id, input.id) })),
});