In this blog I want to show you a nice new feature in Nginx 1.19 Docker image. I requested it somewhere 2 years ago when I was trying to figure out how I could configure my static page applications more flexibly with various endpoints to backing microservices. Back then I used to have my static pages fetch a json file that contained the endpoints for the apis. This way I could simply mount this json file into my container with all kind of endpoints for this particular deployment. It was some sort of service discovery mechanism I applied back then by having my React application fetch this json file as the first step. Now since the Release of Nginx 1.19 Docker image it is finally possible to do this using Environment variables which enables you to use Nginx images in a more immutable fashion. By doing so you can package your application in such way it actually also works with the React development server proxy. In a React project you would for example define this in following way in your package.json.