Environment Variables Completely Missing - Undefined Even After Rebuild/Redeploy

[omur00]

Problem Description
Environment variables set in QuickStack are completely undefined in my Next.js application, during build time it is undefined and missing and runtime. This persists even after multiple rebuilds and redeploys.

Terminal log shows that they are defined but actually not.

Current Behavior
Environment variables (NEXT_PUBLIC_*) are completely undefined

No amount of rebuilding or redeploying fixes the issue

Application fails because required API URLs are missing

Hardcoding values works, but this is not a sustainable solution

Expected Behavior
Environment variables set in QuickStack should be available to the Next.js application both during build and at runtime.

Logs
Read logs from all running Containers.:

Next.js 15.5.2
2025-11-19T17:36:45.427850102Z - Local: http://localhost:xxxx
2025-11-19T17:36:45.427871169Z - Network: http://xxxxxx
2025-11-19T17:36:45.428110884Z
2025-11-19T17:36:45.428254117Z ✓ Starting...
2025-11-19T17:36:45.848208106Z ✓ Ready in 787ms
2025-11-19T17:36:46.175320704Z Environment variables check: {
2025-11-19T17:36:46.175356087Z hasPublicKey: true,
2025-11-19T17:36:46.175360191Z hasPrivateKey: true,
2025-11-19T17:36:46.175363891Z hasUrlEndpoint: true,
2025-11-19T17:36:46.175367248Z privateKeyLength: 36,
2025-11-19T17:36:46.175372075Z urlEndpoint: 'https://ik.imagekit.io/3tfnpu0nu'
2025-11-19T17:36:46.175377589Z }

But logs out in chrome shows that each one of these are undefined.

Environments for my backend app, an express js app is working but for the frontend Next are not.

[biersoeckli]

Hey @omur00

Thanks for reaching out.

Currently env-variables are only supported during runtime (when the application is already deployed), not during the build process.

I'll mark the issue as "enhancement", so that this feature (env vars at build time) will be implemented in the future.

As a workaround for now, you could set env vars at builtime in your Dockerfile with dummy values so the build of your application completes without any errors.

The configuration of env variables at runtime should actually work. Have you tested to open the terminal of your running app and type 'echo $YOUR_ENV_VAR'?
I assume you deployed a Next.JS application? Have you checked to add the Prefix "NEXT_PUBLIC" for all env variables you are accessong in client components (the browser)?Link to Next.JS Documentation

Let me know if you have any further questions :)

[omur00]

I am not sure where is the problem.

Inside my app, in sh terminal i can get echo $NEXT_PUBLIC_ values I put to the env of the app.

Inside my project I load the runtime as follows:

publicRuntimeConfig: {
expressApiUrl: process.env.NEXT_PUBLIC_
}

then anywhere:
import { publicRuntimeConfig } from "../../next.config";
publicRuntimeConfig.expressApiUrl

Locally, in development it works but in production after deploying through QuickStack the expressApiUrl is always wrong or either not getting the runtime from the app env.

proccess.env... also not getting the runtime envs.

This only happens for nextjs while for express it works.

Runtimes env values from app are not working at all. I had to upload .env with the repo.

[omur00]

Do I have to make a copy of .env in Dockerfile ?