Reference:
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/prog/configuration/171/b_171_programmability_cg/model_d YANG (Yet Another Next Generation) is a data modeling language used to model configuration and state data manipulated by network management protocols. YANG interfaces typically support two encoding formats:
JSON: JavaScript Object Notation, a lightweight data interchange format that is easy for humans to read and write.
XML: Extensible Markup Language, a flexible text format used widely for representing structured data.
Reference: Cisco YANG Data Models