Angular allows us to build Angular applications for different environments using the ng build command.

Suppose we have two environment files: and We want to build our Angular application using the environment file for the development environment:

In our angular.json file, we add the following in the development object within the configurations object in order to tell Angular to use the file:

"configurations": {
    "development": {
        "fileReplacements": [
                "replace": "src/environments/environment.ts",
                "with": "src/environments/"

Now, we can run the following command:

ng build --configuration=development.

If you are using Angular 12+, you can find the default configuration when the build command is executed in the build object with the key defaultConfiguration in angular.json.

We can make this process a little simpler by just adding the suffix --configuration= along with the environment that we want in package.json in the scripts object for build. Instead of just ng build, we can tell ng build that we want to build for using the production environment file ng build --configuration=production.

"scripts": {
    "build": "ng build --configuration=production"

Now, we can run ng build using npm: npm build.