Preparing the Project

Before deploying to the server, you need to prepare your NestJS project to ensure it can run correctly in a production environment.

Environment Configuration

If you don't already use a .env file for your environment variables, it is time to create one. It should look something like this:

PORT=3000
DATABASE_URL=...
API_KEY=...

.env.production

You can create a .env.production to cover different environment variables when deploying your application for production. Just create a file like .env.${Node environment mode}. To use it inside your code, just do it like this:

// in AppModule (or ConfigModule import)
ConfigModule.forRoot({
  isGlobal: true,
  envFilePath: `.env${process.env.NODE_ENV ? '.' + process.env.NODE_ENV : ''}`,
});

With that setup, NestJS will be able to pick up the correct environment variable depending on your deployment mode.

Set NODE_ENV When Running the App

To make the magic finally work, all you need to do is set the NODE_ENV mode when deploying.

NODE_ENV=production node dist/main.js

Fallback or shared values

If you want to load both .env and .env.production with .env.production overriding shared values:

ConfigModule.forRoot({
  isGlobal: true,
  envFilePath: ['.env', `.env.${process.env.NODE_ENV}`],
});