Fix · Vercel and deploying

Environment variable missing on Vercel (works locally)

Blocks your workNot checked against the vendor's current screens

What you may see

It works on my computer but shows errors or empty data on the live site
Error says undefined, missing key, or invalid URL

Most likely cause

Your .env file stays on your computer; the live site only knows variables you added in the Vercel project settings.

Check first (about two minutes)

List the variable names in your .env file (names only, never values).
Open the Vercel project settings, the Environment Variables page (it may be labelled differently), and compare names.

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
Environment variable missing on Vercel (works locally)

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
Your .env file stays on your computer; the live site only knows variables you added in the Vercel project settings.

DO THESE STEPS, IN THIS ORDER
1. Search the code for every process.env.<NAME> (or import.meta.env for Vite) and list the names the app uses.
2. Compare that list with the names I will give you from Vercel. Never ask for the values.
3. Tell me which names are missing, which environments (Production, Preview, Development) each must be added to, and how to add them in Vercel.
4. Remind me that a change needs a new deployment, and that variables for the browser need the framework's public prefix (NEXT_PUBLIC_ or VITE_) and are visible to everyone.
Stop and tell me if what you see does not match a step. Do not skip ahead.

CHECK THAT IT WORKED
- After a redeploy the live site shows real data and the error is gone.
Tell me exactly what I should see on the screen when it works.

DO NOT CHANGE
- Do not copy my .env file into the repository or into the code.
- Do not put secret keys in variables with a public prefix.
- 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

Search the code for every process.env.<NAME> (or import.meta.env for Vite) and list the names the app uses.
Compare that list with the names I will give you from Vercel. Never ask for the values.
Tell me which names are missing, which environments (Production, Preview, Development) each must be added to, and how to add them in Vercel.
Remind me that a change needs a new deployment, and that variables for the browser need the framework's public prefix (NEXT_PUBLIC_ or VITE_) and are visible to everyone.

Do not do this

Do not paste real key values into chat; add them directly in Vercel.
Do not copy my .env file into the repository or into the code.
Do not put secret keys in variables with a public prefix.

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