YAML Ain't Markup Language, commonly known as YAML, is a human-readable data serialization format. It is designed to be easily understood and written by humans, making it ideal for configuration files and data exchange between programming languages. Unlike markup languages such as HTML, YAML focuses on data representation rather than document structure. YAML uses indentation to represent nested data structures, which helps maintain clarity and simplicity. It supports various data types, including scalars, lists, and dictionaries, allowing for flexible data organization. Its straightforward syntax makes it popular in applications like Docker and Kubernetes for configuration management.