A config file is a file that stores settings and preferences used by an application. It allows developers to modify behavior without changing source code. Config files commonly include database credentials, API URLs, environment settings, feature flags, or performance parameters. They support flexible deployments across development, staging, and production environments. Formats such as JSON, YAML, TOML, and INI are commonly used for configuration.
How it Works
When an application starts, it reads the config file and loads its values into memory. These values determine how the application initializes connections, logs data, or interacts with external services. Config files can be overridden with environment variables or command line flags. Separating configuration from code helps maintain security and reduces hardcoded values. Good configuration design improves portability and repeatability across systems.