APP_DEPLOYMENT_ENV undefined in production build

[foxlau]

Description

Environment variable APP_DEPLOYMENT_ENV is undefined when running the production build (npm run build && npm start), but works fine in development mode (npm run dev).

Steps to Reproduce

1. .env file exists with APP_DEPLOYMENT_ENV="production"
2. npm run dev - works fine
3. npm run build && npm start - fails with:

DEBUG: Raw process.env: { NODE_ENV: 'production', APP_DEPLOYMENT_ENV: undefined }
❌ Invalid environment variables: { APP_DEPLOYMENT_ENV: [ 'Required' ] }

Environment

• Node.js: v22.12.0
• npm: v10.9.0
• pnpm: v9.14.2
• Works in dev mode (npm run dev)
• Fails only in production build

Could this be related to how environment variables are handled during the production build process?

[thomasfr]

Hi @foxlau thanks for creating the issue.
The build does not include the env vars which are set during the build process (running pnpm run build). When you run your application with pnpm run start it tries to read those environment variables from process.env, if they are not set, it fails with the above error.
During development (pnpm run dev), you dont see this error cause the react-router dev server is automatically trying to load an .env file to load them as environment variables. In production though, they should be set as actual environment variables.
If you want to test that out locally you can try to do:

pnpm run build
APP_DEPLOYMENT_ENV=production pnpm run start

or if you have dotenvx installed globally, you can run this to let dotenvx try to load env vars from an .env file like so:

pnpm run build
dotenvx run -- pnpm run start

On a production server/deployment you should set the environment variables according to the documentation of your chosen deployment platform.