Software Architect's Handbook

Configuration

An application's configuration consists of values that can vary across deployments, such as database connection information, URLs for web services, and SMTP server information for emails.

The configuration for a cloud-native application should be stored in the environment and not in the application code. The configuration will vary depending on the type of deployment (for example, whether the deployment is to development, staging, or production), while the code will not. There should be a strict separation between an application's code and its configuration.