Custom header

The headers option can be customized in the config when using the httpBatchLink or the httpLink.

headers can be both an object or a function. If it's a function it will get called dynamically for every HTTP request.

utils/trpc.ts
ts
// Import the router type from your server file
import type { AppRouter } from '@/server/routers/app';
import { httpBatchLink } from '@trpc/client';
import { createTRPCNext } from '@trpc/next';
export let token: string;
export const trpc = createTRPCNext<AppRouter>({
  config({ ctx }) {
    return {
      links: [
        httpBatchLink({
          url: 'http://localhost:3000/api/trpc',
          /**
           * Headers will be called on each request.
           */
          headers() {
            return {
              Authorization: token,
            };
          },
        }),
      ],
    };
  },
});

utils/trpc.ts
ts
// Import the router type from your server file
import type { AppRouter } from '@/server/routers/app';
import { httpBatchLink } from '@trpc/client';
import { createTRPCNext } from '@trpc/next';
export let token: string;
export const trpc = createTRPCNext<AppRouter>({
  config({ ctx }) {
    return {
      links: [
        httpBatchLink({
          url: 'http://localhost:3000/api/trpc',
          /**
           * Headers will be called on each request.
           */
          headers() {
            return {
              Authorization: token,
            };
          },
        }),
      ],
    };
  },
});

Example with auth login

pages/auth.tsx
ts
const loginMut = trpc.auth.login.useMutation({
  onSuccess({ accessToken }) {
    token = accessToken;
  },
});

pages/auth.tsx
ts
const loginMut = trpc.auth.login.useMutation({
  onSuccess({ accessToken }) {
    token = accessToken;
  },
});

The token can be whatever you want it to be. It's entirely up to you whether that's just a client-side variable that you update the value of on success or whether you store the token and pull it from local storage.