Fix · Vercel and deploying

My API route works locally but returns 404 or fails on the live site

Not checked against the vendor's current screens

What you may see

fetch to /api/... works on my computer but not online
The site is a static export, so the API does not exist

Most likely cause

The live site does not run the server code at that address: a static export, a wrong folder for the route, or a method (GET versus POST) that the route does not handle.

Check first (about two minutes)

Open the full address of the route in a browser tab: do you get 404, 405 or a real answer?
Check if the project is exported as static files (look for output: "export" or a static host setting).

The fix prompt

What you type here never leaves your browser. The search runs on this page, and nothing is sent to a server or to an AI.

The exact error or what you see

What you did before it happened

Kept only in this browser, on this device. Keys and passwords are removed before anything is saved.

Prompt language

You are a patient senior engineer who deploys websites on Vercel every day and explains it to people who are not developers. I am not a developer, so explain every step in plain words and tell me exactly which button, menu or command you mean. If you are not sure about something, say so; do not guess.

Menu and button names change over time. If you cannot find a button or page I mention, say so and tell me what to look for instead of guessing.

THE PROBLEM
My API route works locally but returns 404 or fails on the live site

THE EXACT ERROR OR WHAT I SEE
[paste the exact error here]

WHAT I DID BEFORE IT HAPPENED
[write in a few words what you did before it happened]

MOST LIKELY CAUSE
The live site does not run the server code at that address: a static export, a wrong folder for the route, or a method (GET versus POST) that the route does not handle.

DO THESE STEPS, IN THIS ORDER
1. Check where the route file is and its exact name and exported method (GET, POST).
2. Check the framework setting for static export and whether server code is allowed in this project's host setup.
3. Fix the one cause found and show me a curl command that tests the route.
Stop and tell me if what you see does not match a step. Do not skip ahead.

CHECK THAT IT WORKED
- The curl command returns the expected answer from the live address.
Tell me exactly what I should see on the screen when it works.

DO NOT CHANGE
- Do not move the whole site to another host to fix one route.
- Anything I did not ask about: the design, the text, other pages, other settings or the data.
- Do not delete files, data or branches, do not reset or force-push, and do not rewrite history, unless you first show me exactly what would be lost and I say yes.
- Do not paste, print or ask me to paste a password or secret key into this chat. If one is needed, tell me which settings page of the right service to store it in.

WHEN YOU FINISH
Explain in simple words what you changed (file by file or setting by setting), why you changed it, and how I can undo it.

Paste it into Claude, ChatGPT, Gemini or Cursor, then follow what it says.

After you tried it, did it work?

Steps

Check where the route file is and its exact name and exported method (GET, POST).
Check the framework setting for static export and whether server code is allowed in this project's host setup.
Fix the one cause found and show me a curl command that tests the route.

Do not do this

Do not put secret keys into a static page to avoid the route.
Do not move the whole site to another host to fix one route.

Try another entry