YAML is a data serialization language that is often used for writing configuration files. Depending on whom you ask, YAML stands for yet another markup language or YAML aren’t markup language (a recursive acronym), which emphasizes that YAML is for data, not documents’ is a data-oriented language that has features derived from Perl, C, HTML, and other languages. YAML is a superset of JSON that comes with multiple built-in advantages such as including comments, self-referencing, and support for complex datatypes. Many developers choose to use 4-space or 2-space indentation. In YAML, each nested statement (e.g., a statement following a '{' brace) should be indented exactly once more than the previous line's indentation.)