The docs you're looking for is the externalized configuration section. 14 seems like a lot, but in reality you'll like use only a couple of layers in a product

The docs you're looking for is the externalized configuration section. 14 seems like a lot, but in reality you'll like use only a couple of layers in a production deployment. The reason there's so many is that list is exhaustive and includes sources only relevant to development and testing, as well there are a number of ways you may want to inject environment specific configuration values (command line flags, system properties, jndi, environment variables, etc..), you would normally just pick the one that made sense for your deployment environment. https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-external-config.html https://docs.spring.io/spring-boot/docs/current/reference/ht...