The ability to have real-time two-way communication between the client and the server is a key feature in most modern web apps.

A common pattern when deploying applications to a development, staging, and production environment is to build a jar or docker image one time, then supply different configuration values in the deployment for each stage. This configuration could be a Spring profile in separate yaml documents, additional properties files, environment variables, or some other configuration mechanism.

Recently, I’ve had an issue were I want to be able to run multiple spring boot services locally for testing and development purposes. Unfortunately they all run on the same port so they fail to start!