What is Viper used for?

Viper is used for managing configuration in Go applications, providing a flexible and efficient way to handle settings across different environments. It enables developers to read configuration from very different sources: JSON, YAML, TOML files; environment variables; command-line flags; or even from remote configuration systems. Viper provides live reloading of configuration-so there is no requirement of restarting the application due to configuration changes.
Viper lets the developers centralize and simplify the way configuration management is handled, thus enabling smooth transitions across environments, from development to testing and then into production. Therefore, it is one of the most-used tools by Go developers in creating complex applications that require adaptable and organized handling of configurations.