Anyone came up with a solution for this yet?

According to the Next.js docs, NEXT_PUBLIC_ variables are "inlined" into the JavaScript bundle at BUILD TIME, not runtime. This means:

1. You need the environment variable available in the builder stage of your Dockerfile where next build happens

2. After the build, these values are frozen and won't respond to runtime changes

Yet this still doesn't work in my Dockerfile:

```

# In the builder stage where next build happens

FROM base AS builder

ARG RAILWAY_PUBLIC_DOMAIN # Get Railway's domain as build arg

# Set NEXT_PUBLIC_ var during build - this is when Next.js inlines it

ENV NEXT_PUBLIC_APP_URL=https://${RAILWAY_PUBLIC_DOMAIN}

# Then do your build

RUN pnpm build --filter=${PROJECT}

```

Hey! I saw your issue and wanted to help. This kind of problem usually comes from environment variables not being passed correctly during Railway’s Docker build/deploy process. Even if turbo.json or .env works locally, Railway won’t automatically use them unless you set them explicitly.

Here are a few things you can try:

1. Set env vars directly in Railway’s dashboard:
   Go to your Railway project → Variables tab → add all the environment variables your app needs (even if they’re already in .env locally).

2. If you use a Dockerfile, make sure build-time vars are handled:

ARG MY_VAR

ENV MY_VAR=$MY_VAR

Then in railway.json, you can pass them like this:

{

"build": {

"env": {

"MY_VAR": "your-value"

}

}

}

3. Check t3-env behavior:
   t3-env can sometimes fail silently if the environment variables are missing or not loaded during build. Try logging a few key vars in production to confirm they’re loaded:

console.log(process.env.YOUR_VAR_NAME);

I was making 2 mistakes actually:

1. I tested multiple scenarios, and when I wrote my latest reply, I removed the thing you are talking about at point 2.

2. I was using a z.string().url() validation on the RAILWAY_PUBLIC_DOMAIN, which doesn't include the protocol scheme, so ofc it was failing