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We highly encourage you to check out the Example Apps to get a feel of tRPC and getting up & running as seamless as possible.


โš ๏ธ Requirements: tRPC requires TypeScript > 4.1 as it relies on Template Literal Types.

npm install @trpc/server

For implementing tRPC endpoints and routers. Install in your server codebase.

npm install @trpc/client

For making typesafe API calls from your client. Install in your client codebase.

npm install @trpc/react

For generating a powerful set of React hooks for querying your tRPC API. Recommended for non-Next.js React projects. Powered by react-query.

npm install @trpc/next

A set of utilies for integrating tRPC with Next.js.

Installation Snippets#


npm install @trpc/server @trpc/client @trpc/react @trpc/next


yarn add @trpc/server @trpc/client @trpc/react @trpc/next

Defining a router#

Let's walk through the steps of building a typesafe API with tRPC. To start, this API will only contain two endpoints:

getUser(id: string) => { id: string; name: string; }createUser(data: {name:string}) => { id: string; name: string; }

Create a router instance#

First we define a router somewhere in our server codebase:

// server/index.tsimport * as trpc from '@trpc/server';const appRouter = trpc.router();
// only export *type signature* of router!// to avoid accidentally importing your API// into client-side codeexport type AppRouter = typeof appRouter;

Add a query endpoint#

Use the .query() method to add a query endpoint to the router. Arguments:

.query(name: string, params: QueryParams)

  • name: string: The name of this endpoint
  • params.input: Optional. This should be a function that validates/casts the input of this endpoint and either returns a strongly typed value (if valid) or throws an error (if invalid). Alternatively you can pass a Zod, Superstruct or Yup schema.
  • params.resolve: This is the actual implementation of the endpoint. It's a function with a single req argument. The validated input is passed into req.input and the context is in req.ctx (more about context later!)
// server/index.tsimport * as trpc from '@trpc/server';
const appRouter = trpc.router().query('getUser', {  input: (val: unknown) => {    if (typeof val === 'string') return val;    throw new Error(`Invalid input: ${typeof val}`);  },  async resolve(req) {    req.input; // string    return { id: req.input, name: 'Bilbo' };  },});
export type AppRouter = typeof appRouter;

Add a mutation endpoint#

Similarly to GraphQL, tRPC makes a distinction between query and mutation endpoints. Let's add a createUser mutation:

createUser(payload: {name: string}) => {id: string; name: string};
// server/index.tsimport * as trpc from '@trpc/server';import { z } from 'zod';
const appRouter = trpc  .router()  .query('getUser', {    input: (val: unknown) => {      if (typeof val === 'string') return val;      throw new Error(`Invalid input: ${typeof val}`);    },    async resolve(req) {      req.input; // string      return { id: req.input, name: 'Bilbo' };    },  })  .mutation('createUser', {    // validate input with Zod    input: z.object({ name: z.string().min(5) }),    async resolve(req) {      // use your ORM of choice      return await UserModel.create({        data: req.input,      });    },  });
export type AppRouter = typeof appRouter;

Next steps#

tRPC includes more sophisticated client-side tooling designed for React projects generally and Next.js specifically. Read the appropriate guide next: