Usage with Next.js

Next.js makes it easy for you to build your client and server together in one codebase. tRPC makes it easy to share types between them, ensuring typesafety for your application's data fetching.

tip

If you're using tRPC in a new project, consider using one of the example projects as a starting point or for reference: tRPC Example Projects

Recommended file structure

We recommend a file structure like this one, although it is not enforced by tRPC. This is what you'll get when starting from the examples.

graphql
.
├── prisma  # <-- if prisma is added
│   └── [..]
├── src
│   ├── pages
│   │   ├── _app.tsx  # <-- add `withTRPC()`-HOC here
│   │   ├── api
│   │   │   └── trpc
│   │   │       └── [trpc].ts  # <-- tRPC HTTP handler
│   │   └── [..]
│   ├── server
│   │   ├── routers
│   │   │   ├── _app.ts  # <-- main app router
│   │   │   ├── post.ts  # <-- sub routers
│   │   │   └── [..]
│   │   ├── context.ts   # <-- create app context
│   │   └── trpc.ts      # <-- procedure helpers
│   └── utils
│       └── trpc.ts  # <-- your typesafe tRPC hooks
└── [..]

graphql
.
├── prisma  # <-- if prisma is added
│   └── [..]
├── src
│   ├── pages
│   │   ├── _app.tsx  # <-- add `withTRPC()`-HOC here
│   │   ├── api
│   │   │   └── trpc
│   │   │       └── [trpc].ts  # <-- tRPC HTTP handler
│   │   └── [..]
│   ├── server
│   │   ├── routers
│   │   │   ├── _app.ts  # <-- main app router
│   │   │   ├── post.ts  # <-- sub routers
│   │   │   └── [..]
│   │   ├── context.ts   # <-- create app context
│   │   └── trpc.ts      # <-- procedure helpers
│   └── utils
│       └── trpc.ts  # <-- your typesafe tRPC hooks
└── [..]

Add tRPC to existing Next.js project

1. Install deps

npm

sh
npm install @trpc/server @trpc/client @trpc/react-query @trpc/next @tanstack/react-query zod

sh
npm install @trpc/server @trpc/client @trpc/react-query @trpc/next @tanstack/react-query zod

yarn

sh
yarn add @trpc/server @trpc/client @trpc/react-query @trpc/next @tanstack/react-query zod

sh
yarn add @trpc/server @trpc/client @trpc/react-query @trpc/next @tanstack/react-query zod

pnpm

sh
pnpm add @trpc/server @trpc/client @trpc/react-query @trpc/next @tanstack/react-query zod

sh
pnpm add @trpc/server @trpc/client @trpc/react-query @trpc/next @tanstack/react-query zod

Two packages of note:

• @tanstack/react-query: @trpc/react-query provides a thin wrapper around react-query. It is required as a peer dependency as an idiomatic way to handle client-side caching in React applications.
• Zod: We will use Zod for input validation to ensure that our backend only processes requests that fit our API. You can use other validation libraries like Yup, Superstruct, io-ts if you prefer.

2. Enable strict mode

If you want to use Zod for input validation, make sure you have enabled strict mode in your tsconfig.json:

tsconfig.json
diff
"compilerOptions": {
+   "strict": true
}

tsconfig.json
diff
"compilerOptions": {
+   "strict": true
}

If strict mode is too harsh, you'll at least want to enable strictNullChecks:

tsconfig.json
diff
"compilerOptions": {
+   "strictNullChecks": true
}

tsconfig.json
diff
"compilerOptions": {
+   "strictNullChecks": true
}

3. Create a tRPC router

Initialize your tRPC backend using the initTRPC function and create your first router. We're going to make a simple "hello world" router and procedure here - but be sure to browse the rest of the docs for information about creating more complex APIs.

View sample backend

server/trpc.ts
ts
import { TRPCError, initTRPC } from '@trpc/server';
// Avoid exporting the entire t-object
// since it's not very descriptive.
// For instance, the use of a t variable
// is common in i18n libraries.
const t = initTRPC.create();
// Base router and procedure helpers
export const router = t.router;
export const procedure = t.procedure;

server/trpc.ts
ts
import { TRPCError, initTRPC } from '@trpc/server';
// Avoid exporting the entire t-object
// since it's not very descriptive.
// For instance, the use of a t variable
// is common in i18n libraries.
const t = initTRPC.create();
// Base router and procedure helpers
export const router = t.router;
export const procedure = t.procedure;

server/routers/_app.ts
ts
import { z } from 'zod';
import { procedure, router } from '../trpc';
export const appRouter = router({
  hello: procedure
    .input(
      z.object({
        text: z.string(),
      }),
    )
    .query(({ input }) => {
      return {
        greeting: `hello ${input.text}`,
      };
    }),
});
// export type definition of API
export type AppRouter = typeof appRouter;

server/routers/_app.ts
ts
import { z } from 'zod';
import { procedure, router } from '../trpc';
export const appRouter = router({
  hello: procedure
    .input(
      z.object({
        text: z.string(),
      }),
    )
    .query(({ input }) => {
      return {
        greeting: `hello ${input.text}`,
      };
    }),
});
// export type definition of API
export type AppRouter = typeof appRouter;

pages/api/trpc/[trpc].ts
ts
import * as trpcNext from '@trpc/server/adapters/next';
import { appRouter } from '../../../server/routers/_app';
// export API handler
export default trpcNext.createNextApiHandler({
  router: appRouter,
  createContext: () => ({}),
});

pages/api/trpc/[trpc].ts
ts
import * as trpcNext from '@trpc/server/adapters/next';
import { appRouter } from '../../../server/routers/_app';
// export API handler
export default trpcNext.createNextApiHandler({
  router: appRouter,
  createContext: () => ({}),
});

note

The backend above is using the recommended file structure, but you can keep it simple and put everything in an API handler directly if you prefer.

4. Create tRPC hooks

Create a set of strongly-typed hooks using your API's type signature.

utils/trpc.ts
tsx
import { httpBatchLink } from '@trpc/client';
import { createTRPCNext } from '@trpc/next';
import type { AppRouter } from '../server/routers/_app';
function getBaseUrl() {
  if (typeof window !== 'undefined')
    // browser should use relative path
    return '';
  if (process.env.VERCEL_URL)
    // reference for vercel.com
    return `https://${process.env.VERCEL_URL}`;
  if (process.env.RENDER_INTERNAL_HOSTNAME)
    // reference for render.com
    return `http://${process.env.RENDER_INTERNAL_HOSTNAME}:${process.env.PORT}`;
  // assume localhost
  return `http://localhost:${process.env.PORT ?? 3000}`;
}
export const trpc = createTRPCNext<AppRouter>({
  config({ ctx }) {
    return {
      links: [
        httpBatchLink({
          /**
           * If you want to use SSR, you need to use the server's full URL
           * @link https://trpc.io/docs/ssr
           **/
          url: `${getBaseUrl()}/api/trpc`,
        }),
      ],
      /**
       * @link https://tanstack.com/query/v4/docs/reference/QueryClient
       **/
      // queryClientConfig: { defaultOptions: { queries: { staleTime: 60 } } },
    };
  },
  /**
   * @link https://trpc.io/docs/ssr
   **/
  ssr: false,
});

utils/trpc.ts
tsx
import { httpBatchLink } from '@trpc/client';
import { createTRPCNext } from '@trpc/next';
import type { AppRouter } from '../server/routers/_app';
function getBaseUrl() {
  if (typeof window !== 'undefined')
    // browser should use relative path
    return '';
  if (process.env.VERCEL_URL)
    // reference for vercel.com
    return `https://${process.env.VERCEL_URL}`;
  if (process.env.RENDER_INTERNAL_HOSTNAME)
    // reference for render.com
    return `http://${process.env.RENDER_INTERNAL_HOSTNAME}:${process.env.PORT}`;
  // assume localhost
  return `http://localhost:${process.env.PORT ?? 3000}`;
}
export const trpc = createTRPCNext<AppRouter>({
  config({ ctx }) {
    return {
      links: [
        httpBatchLink({
          /**
           * If you want to use SSR, you need to use the server's full URL
           * @link https://trpc.io/docs/ssr
           **/
          url: `${getBaseUrl()}/api/trpc`,
        }),
      ],
      /**
       * @link https://tanstack.com/query/v4/docs/reference/QueryClient
       **/
      // queryClientConfig: { defaultOptions: { queries: { staleTime: 60 } } },
    };
  },
  /**
   * @link https://trpc.io/docs/ssr
   **/
  ssr: false,
});

note

createTRPCNext does not work with interop mode. If you are migrating from v9 using interop, keep using the old way of initializing tRPC.

5. Configure _app.tsx

pages/_app.tsx
tsx
import type { AppType } from 'next/app';
import { trpc } from '../utils/trpc';
const MyApp: AppType = ({ Component, pageProps }) => {
  return <Component {...pageProps} />;
};
export default trpc.withTRPC(MyApp);

pages/_app.tsx
tsx
import type { AppType } from 'next/app';
import { trpc } from '../utils/trpc';
const MyApp: AppType = ({ Component, pageProps }) => {
  return <Component {...pageProps} />;
};
export default trpc.withTRPC(MyApp);

6. Make an API request

pages/index.tsx
tsx
import { trpc } from '../utils/trpc';
export default function IndexPage() {
  const hello = trpc.hello.useQuery({ text: 'client' });
  if (!hello.data) {
    return <div>Loading...</div>;
  }
  return (
    <div>
      <p>{hello.data.greeting}</p>
    </div>
  );
}

pages/index.tsx
tsx
import { trpc } from '../utils/trpc';
export default function IndexPage() {
  const hello = trpc.hello.useQuery({ text: 'client' });
  if (!hello.data) {
    return <div>Loading...</div>;
  }
  return (
    <div>
      <p>{hello.data.greeting}</p>
    </div>
  );
}

createTRPCNext() options

config-callback

The config-argument is a function that returns an object that configures the tRPC and React Query clients. This function has a ctx input that gives you access to the Next.js req object, among other things. The returned value can contain the following properties:

• Required:
• links to customize the flow of data between tRPC Client and the tRPC Server. Read more.
• Optional:
• queryClientConfig: a configuration object for the React Query QueryClient used internally by the tRPC React hooks: QueryClient docs
• queryClient: a React Query QueryClient instance
  • Note: You can only provide either a queryClient or a queryClientConfig.
• transformer: a transformer applied to outgoing payloads. Read more about Data Transformers
• abortOnUnmount: determines if in-flight requests will be cancelled on component unmount. This defaults to false.

unstable_overrides: (default: undefined)

Configure overrides for React Query's hooks.

ssr-boolean (default: false)

Whether tRPC should await queries when server-side rendering a page. Defaults to false.

responseMeta-callback

Ability to set request headers and HTTP status when server-side rendering.

Example

utils/trpc.ts
tsx
import { createTRPCNext } from '@trpc/next';
import type { AppRouter } from '../pages/api/trpc/[trpc]';
export const trpc = createTRPCNext<AppRouter>({
  config({ ctx }) {
    /* [...] */
  },
  ssr: true,
  responseMeta({ clientErrors, ctx }) {
    if (clientErrors.length) {
      // propagate first http error from API calls
      return {
        status: clientErrors[0].data?.httpStatus ?? 500,
      };
    }
    // cache full page for 1 day + revalidate once every second
    const ONE_DAY_IN_SECONDS = 60 * 60 * 24;
    return {
      'Cache-Control': `s-maxage=1, stale-while-revalidate=${ONE_DAY_IN_SECONDS}`,
    };
  },
});

utils/trpc.ts
tsx
import { createTRPCNext } from '@trpc/next';
import type { AppRouter } from '../pages/api/trpc/[trpc]';
export const trpc = createTRPCNext<AppRouter>({
  config({ ctx }) {
    /* [...] */
  },
  ssr: true,
  responseMeta({ clientErrors, ctx }) {
    if (clientErrors.length) {
      // propagate first http error from API calls
      return {
        status: clientErrors[0].data?.httpStatus ?? 500,
      };
    }
    // cache full page for 1 day + revalidate once every second
    const ONE_DAY_IN_SECONDS = 60 * 60 * 24;
    return {
      'Cache-Control': `s-maxage=1, stale-while-revalidate=${ONE_DAY_IN_SECONDS}`,
    };
  },
});

Next steps

Browse the rest of the docs to learn more about things like authorization, middlewares, and error handling.

You can also find usual information about queries and mutations now that you're using @trpc/react-query.