TypeError: fetch failed when deploying to Vercel (Next.js)

Question

I'm building a website using next.js which uses Route Handlers. When I run the npm run build command it works perfectly fine, but when I deploy to Vercel it shows this error: TypeError: fetch failed at Object.fetch (node:internal/deps/undici/undici:11457:11) at process.processTicksAndRejections (node:internal/process/task_queues:95:5) { cause: Error: connect ECONNREFUSED 127.0.0.1:3000 at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1494:16) at TCPConnectWrap.callbackTrampoline (node:internal/async_hooks:130:17) { errno: -111, code: 'ECONNREFUSED', syscall: 'connect', address: '127.0.0.1', port: 3000 } } Error: Command "npm run build" exited with 1 Can someone tell me where the issue is? There no errors in the browser console, nor in the build command. Here is my code:

import React from 'react'
import { Search } from '@/components'

async function getJobs() {
  const res = await fetch('http://localhost:3000/api/jobs');
  if (!res.ok) {
    throw new Error("Couldn't fetch")
  }
  const data = await res.json();
  return data;
}

export default async function Home() {
  const jobs = await getJobs();

  return (
    <main className='px-6 md:px-8'>
      <Search />
      <pre>{ JSON.stringify(jobs, null, 2)}</pre>
      <span>{new Date().getTime()}</span>
    </main> 
  )
}

export const revalidate = 900;

Any help is appreciated. If you need more information about this problem, feel free to ask. Thanks in advance

Answer 1

To solve that, add a .env file at the project root with an enviroment variable receiveing the 'http://localhost:3000' value, then import to your fetch url by using ${process.env.NAME_OF_YOUR_ENV_VARIABLE}/api/jobs. then go to your dashboard in vercel and set the value of NAME_OF_YOUR_ENV_VARIABLE as the base url of the deploy gave by vercel.

Answer 2

in next.config.js write env:{} https://nextjs.org/docs/pages/api-reference/next-config-js/env for exp.

env: { API_URL: "https://yours-project.vercel.app"} and use this API_URL in fetch
const apiUrl = process.env.API_URL;
const res = await fetch(`${apiUrl}/api/jobs`, {
cache: "no-store",
});

it helped me.