What is a YAML?

YAML was designed explicitly to be easier for humans to read and hand-edit than JSON or XML, which is why it dominates configuration files: CI/CD pipeline definitions, Kubernetes manifests, and application config all favor YAML over JSON when a person is expected to write or review the file directly. It achieves this readability by using whitespace indentation to signal nesting instead of braces and brackets, and by allowing comments, which JSON does not support at all. That same reliance on whitespace is YAML's biggest practical pitfall: an inconsistent indent, a stray tab character instead of spaces, or an unquoted value that YAML silently coerces to an unexpected type, such as the string "no" becoming the boolean false, can produce a config that parses successfully but means something different than the author intended. Because of this, most tooling that consumes YAML pairs it with a schema validator to catch these silent misinterpretations before they cause a runtime failure.