YAML

YAML is a data serialization language designed for readability and simplicity, making it popular for configuration files, automation scripts, and data sharing. Unlike XML or JSON, it uses indentation, key-value pairs, and lists instead of heavy syntax with brackets or tags. 

YAML is a superset of JSON, meaning valid JSON files can also be interpreted as YAML. Its clean structure supports data types like strings, numbers, booleans, and multi-line strings, while forbidding tab characters to avoid syntax errors. YAML documents rely on consistent spacing to define nesting, allowing complex data structures to be represented clearly. 

Common use cases include Kubernetes resource definitions, Ansible playbooks, and CI/CD pipelines. Developers prefer YAML for its human-readable format, but tools like linters help ensure valid syntax. While newer formats like JSON are faster for machines, YAML remains a go-to choice for human-friendly configuration and structured data.