Setting Up Your First tRPC Project
Walk through installing tRPC, creating a router, and wiring a client to make your very first type-safe call.
Setting Up Your First tRPC Project is a free tRPC End-to-End Type Safe APIs lesson on CoddyKit — lesson 4 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the tRPC End-to-End Type Safe APIs learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
What We Are Building
You know what tRPC is and why type safety matters. Now you'll set up a real project and make your first end-to-end type-safe call.
Installing the Packages
tRPC ships as separate server and client packages. Install them alongside Zod for validation.
npm install @trpc/server @trpc/client zodInitializing tRPC
Create one t object with initTRPC.create() — everything else (router, procedures) is built from it.
import { initTRPC } from "@trpc/server";
const t = initTRPC.create();
export const router = t.router;
export const publicProcedure = t.procedure;Creating a Router
A router groups procedures. Here's a minimal one exposing a single greeting query.
export const appRouter = router({
hello: publicProcedure.query(() => {
return "Hello tRPC";
}),
});Exporting the Router Type
The core trick: export only the router's type, not its code. The client learns the full API shape with zero codegen.
export type AppRouter = typeof appRouter;Serving the Router
Attach your router to an HTTP server using a tRPC adapter — here, the standalone createHTTPServer.
import { createHTTPServer } from "@trpc/server/adapters/standalone";
createHTTPServer({ router: appRouter }).listen(3000);Creating the Client
The client imports the AppRouter type to unlock full autocomplete and type checking against your server.
import { createTRPCClient, httpBatchLink } from "@trpc/client";
import type { AppRouter } from "./server";
const client = createTRPCClient<AppRouter>({
links: [httpBatchLink({ url: "http://localhost:3000" })],
});Making the First Call
Call the procedure as if it were a local typed function — that's the whole point of tRPC.
const greeting = await client.hello.query();
console.log(greeting); // "Hello tRPC"Type Safety in Action
Type safety in action: rename hello on the server and the client call becomes a compile error instantly — no runtime surprise.
Project Structure
A common project layout: server/trpc.ts for the t object, server/router.ts for procedures, and client/index.ts for the typed client.
Adding Inputs
Most procedures take input. Validate it with Zod and that input type flows to the client automatically.
greet: publicProcedure
.input(z.object({ name: z.string() }))
.query(({ input }) => "Hi " + input.name),Quick Check
Test your setup knowledge.
Recap
Recap: you installed the tRPC packages, built a router and exported its type, and made a typed client call — a full end-to-end type-safe pipeline.
Frequently asked questions
Is the “Setting Up Your First tRPC Project” lesson free?
Yes — the full text of “Setting Up Your First tRPC Project” is free to read here on the web, and the tRPC End-to-End Type Safe APIs course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the tRPC End-to-End Type Safe APIs course, upgrade to CoddyKit PRO.
What will I learn in “Setting Up Your First tRPC Project”?
Walk through installing tRPC, creating a router, and wiring a client to make your very first type-safe call. You practise tRPC End-to-End Type Safe APIs with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start tRPC End-to-End Type Safe APIs?
No prior experience is required. tRPC End-to-End Type Safe APIs on CoddyKit is structured for beginners through advanced learners; this is — lesson 4 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Setting Up Your First tRPC Project” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this tRPC End-to-End Type Safe APIs lesson?
Yes. Every tRPC End-to-End Type Safe APIs lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- What is tRPC?
- The Power of Type Safety
- tRPC Core Concepts Overview
- Setting Up Your First tRPC Project