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TypeError: fetch failed (ECONNREFUSED)

TypeError: fetch failed
  [cause]: Error: connect ECONNREFUSED 127.0.0.1:3000

In one sentence: Your server-side code tried to call an address where nothing was listening, very often localhost.

What it means

ECONNREFUSED means the computer at that address answered "nothing is running on that port." `127.0.0.1` and `localhost` always mean "this same machine," so on a server they point at the server itself, not your laptop.

In Next.js this usually happens when a Server Component or API route fetches your own API with a full URL like `http://localhost:3000/api/...`. It may work on your computer and then fail once deployed, or during the build when no server is running yet.

Common causes

• Fetching `http://localhost:3000/...` from server code in production, where your app isn't on localhost.
• A Server Component fetching its own API route during `next build`, before any server exists.
• The backend, database, or local API you are calling isn't running, or is on a different port.
• An environment variable for the API URL is missing in production, so the code falls back to localhost.

How to fix it

1. In Server Components, don't fetch your own API routes. Call the shared function or database query directly instead.
2. When you must call another service, read its URL from an environment variable and set that variable in your host's settings for production.
3. Locally, make sure the service you're calling is actually running on that port.
4. Print the full URL right before the fetch so you can see what address it's really using.

// app/page.tsx (Server Component)
const res = await fetch("http://localhost:3000/api/products");
const products = await res.json();

// app/page.tsx (Server Component)
import { getProducts } from "@/lib/products"; // same code the API route uses
const products = await getProducts();

Prompt to paste into your AI tool

My Next.js server code fails with 'fetch failed ECONNREFUSED 127.0.0.1'. Replace server-side fetches to my own API routes with direct calls to the shared data functions, move any external URLs into environment variables, and don't hardcode localhost.

Related errors

• TypeError: Cannot read properties of undefined
• CORS error: blocked by CORS policy
• Hydration failed: server HTML didn't match the client (Next.js)
• Module not found: Can't resolve '...'