Standard Angular builds bake environment variables into the code at build time. This means if you have Dev , Staging , and Prod environments, you have to build the app three times. That's a waste of time. Instead, we should build a single Docker image and swap configurations at runtime. Here is how to do it. 1. The Strategy We will store environment-specific configurations in JSON files and use an Entrypoint script in Docker to swap them based on an environment variable. Step 1: Create Config Files In your src/config folder, create: app-config.dev.json app-config.prod.json In your src/ folder, create a default app-config.json for local development. Step 2: Update angular.json Ensure these files are included in your build assets: "assets" : [ "src/favicon.ico" , "src/assets" , "src/app-config.json" , "src/config" ] 2. The Angular Logic We need to load the JSON file before the app starts. The Config Service Create a service to fetch the JSON file using HttpClient . @ Injectable ({ providedIn : ' root ' }) export class ConfigService { private config : any ; constructor ( private http : HttpClient ) {} loadConfig () { return firstValueFrom ( this . http . get ( ' ./app-config.json ' )) . then ( data => this . config = data ); } get settings () { return this . config ; } } The App Initializer Use APP_INITIALIZER in your app.config.ts (Standalone) or AppModule to block the bootstrap process until the config is loaded. export function initApp ( configService : ConfigService ) { return () => configService . loadConfig (); } // In providers: { provide : APP_INITIALIZER , useFactory : initApp , deps : [ ConfigService ], multi : true } 3. The Docker Magic Now, we create a Docker image that can adapt to its environment. entrypoint.sh This script runs when the container starts. It checks the ENVIRONMENT variable and overwrites the main config file. #!/bin/bash if [[ ENVIRONMENT == "Prod" ]] ; then cp /usr/share/nginx/html/config/app-config.prod.json /usr/share/nginx/html/app-config.json else cp /usr/share/nginx/html/config/app-config.dev.json /usr/share/nginx/html/app-config.json fi nginx -g 'daemon off;' Dockerfile Use a multi-stage build to compile the app and serve it with Nginx. # Build Stage FROM node:lts AS build WORKDIR /app COPY . . RUN npm install && npm run build # Run Stage FROM nginx:latest COPY --from=build /app/dist/your-app-name/browser /usr/share/nginx/html COPY ./entrypoint.sh /entrypoint.sh RUN chmod +x /entrypoint.sh ENTRYPOINT ["/bin/bash", "/entrypoint.sh"] 4. Running the Container Now you can build your image once: docker build -t my-angular-app . And run it anywhere by just changing the environment variable: # Run for Production docker run -e ENVIRONMENT = Prod -p 8080:80 my-angular-app # Run for Dev docker run -e ENVIRONMENT = Dev -p 8080:80 my-angular-app Summary One Build: Saves CI/CD time. Nginx: High-performance serving. Environment Agnostic: Move the same artifact from Dev to Prod with zero code changes. Happy coding! 🚀