External Configuration
External Configuration is a software design principle where configuration settings (e.g., database connections, API keys, feature flags) are stored outside the application code, typically in files, environment variables, or external services. This separates configuration from logic, allowing the same application to run in different environments (development, testing, production) without code changes. It enhances flexibility, security, and maintainability by centralizing and externalizing runtime parameters.
Developers should use External Configuration to manage environment-specific settings, avoid hardcoding sensitive data like passwords, and enable dynamic updates without redeploying code. It's essential for modern cloud-native applications, microservices architectures, and DevOps practices, as it supports continuous integration/deployment (CI/CD) and configuration management tools. Use cases include deploying apps across multiple regions, scaling services with different resource limits, and toggling features in A/B testing.