medium severity

How to Fix: Environment Variable Undefined

Environment variables are undefined in your application, causing features to break.

env variable undefinedprocess.env undefinednext_publicdotenv not working

Symptoms

process.env.VAR_NAME is undefined

API keys missing in production

Different behavior in dev vs production

Common Causes

01

Missing NEXT_PUBLIC_ prefix for client-side vars

02

.env file not in correct location

03

Environment not set in deployment platform

04

Using server-only vars in client components

The DevConsole Solution

DevConsole shows all accessible environment variables and their values (with secrets masked).

Step-by-Step Fix

1

Check Variable Names

Ensure client-side vars start with NEXT_PUBLIC_

2

Verify .env Files

Check .env.local, .env.production, etc.

3

Check Deployment Config

Ensure vars are set in your hosting platform.

Get DevConsoleDocumentation

Frequently Asked Questions

Why do I need NEXT_PUBLIC prefix?

Next.js only exposes env vars starting with NEXT_PUBLIC_ to the browser for security.

Can I use server-only vars in API routes?

Yes! API routes run on server, so they can access all env vars.

Related Problems

401 Unauthorized Error

Your API returns 401 Unauthorized, meaning the server doesn't recognize your credentials or your token has expired.

Module Not Found Error

Your bundler can't find a module you're trying to import, causing build failures.

Stop debugging blindly

DevConsole gives you the visibility and control to fix issues like environment variable undefined in seconds, not hours.

Get DevConsole Pro