Externalizing configurations

The Externalize configurations principle gives you an advice to externalize all configuration parameters from the code. An application's configuration parameters vary between environments such as support email IDs or URL of an external system, username, passwords, queue name, and more. These will be different for development, testing, and production. All service configurations should be externalized:

The same principle is obvious for microservices as well. Microservices configuration parameters should be loaded from an external source. This will also help you automate the release and deployment process as the only change between these environments are the configuration parameters.