End-to-End Type Safety with tRPC
Add tRPC to a SvelteKit project for fully typed client-server communication.
End-to-End Type Safety with tRPC is a free Sveltejs Academy 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 Sveltejs Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
What tRPC Is
tRPC enables fully typed API calls without code generation: server types flow directly to clients.
Install
Add tRPC and a SvelteKit adapter.
npm install @trpc/server @trpc/client trpc-sveltekitDefine Routers
Procedures are typed functions grouped into routers.
export const appRouter = router({
users: router({
list: publicProcedure.query(() => db.select().from(users))
})
});SvelteKit Handler
Mount the router at /trpc/[...path]/+server.js.
Client Setup
Create a typed tRPC client that infers types from the router.
export const trpc = createTRPCSvelteClient<AppRouter>();Type-Safe Calls
The client autocompletes procedures and infers argument and return types.
const users = await trpc.users.list.query();Validation
Pair with Zod schemas for input validation and types in one place.
Mutations
Use publicProcedure.input(z.object({...})).mutation() for typed mutations.
Middleware
Add tRPC middleware for auth, logging, or rate limiting before procedures run.
SSR Friendly
tRPC works with SvelteKit's SSR via the trpc-sveltekit adapter.
Compared to REST/GraphQL
tRPC removes the schema layer; client and server share TypeScript types directly.
Quick Check
What is the main benefit of tRPC?
Recap
tRPC gives end-to-end type-safe API calls in SvelteKit, removing the need for OpenAPI or GraphQL schemas.
Frequently asked questions
Is the “End-to-End Type Safety with tRPC” lesson free?
Yes — the full text of “End-to-End Type Safety with tRPC” is free to read here on the web, and the Sveltejs Academy 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 Sveltejs Academy course, upgrade to CoddyKit PRO.
What will I learn in “End-to-End Type Safety with tRPC”?
Add tRPC to a SvelteKit project for fully typed client-server communication. You practise Sveltejs Academy 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 Sveltejs Academy?
No prior experience is required. Sveltejs Academy 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 “End-to-End Type Safety with tRPC” 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 Sveltejs Academy lesson?
Yes. Every Sveltejs Academy 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
- Auth + Database + API: Architecture
- Drizzle ORM with SvelteKit
- Deploying to Vercel with a Database
- End-to-End Type Safety with tRPC