If your API reside on a different origin than your front-end and wish to send cookies to it, you will need to enable CORS on your server and send cookies with your requests by providing the option {credentials: "include"} to fetch.

The arguments provided to the fetch function used by tRPC can be modified as follow.

app.ts

ts

import { createTRPCClient } from '@trpc/client';

const client = createTRPCClient<AppRouter>({

url: 'YOUR_SERVER_URL',

fetch(url, options) {

`return fetch(url, {`

  `...options,`

  `credentials: 'include',`

`});`

},

});