Both YAML and JSON are case-sensitive data serialization formats. In both languages, the keys (or names) within a key-value pair are treated as strings, and their comparison is case-sensitive. For example, in a JSON object, the key "hostname" is considered different from "Hostname". Similarly, in a YAML mapping, the key hostname: is distinct from Hostname:. This is a fundamental characteristic of how parsers for both formats interpret and structure data.

A. JSON does not use indentation for structure; it uses braces and brackets. Only YAML relies on indentation to define nesting and hierarchy.

B. Whitespace, specifically indentation, is syntactically significant in YAML for defining structure. In JSON, whitespace outside of string values is ignored.

C. YAML supports single-line comments beginning with a # character. The official JSON specification (RFC 8259) does not include a syntax for comments.

1. Juniper Networks Official Documentation: In the Getting Started with Junos Automation guide, the "Data Serialization and Data Models" chapter explicitly states the properties of these formats. It confirms, "YAML is case-sensitive" and "JSON object members are case-sensitive." It also clarifies that "YAML uses indentation to denote structure" while JSON does not, and that "JSON does not support comments."

Source: Juniper Networks TechLibrary, Getting Started with Junos Automation, Chapter: "Data Serialization and Data Models".

2. Official JSON Standard (RFC 8259): This document defines the JSON format. While it doesn't use the exact phrase "case-sensitive," Section 8.1, "String and Character Issues," recommends that implementations treat two name strings as equal "if and only if they are identical (the same sequence of code points)," which implies case-sensitivity. The grammar in Section 2 also shows whitespace is insignificant between structural tokens.

Source: IETF RFC 8259, The JavaScript Object Notation (JSON) Data Interchange Format, Sections 2 ("JSON Grammar") and 8.1 ("String and Character Issues").

3. Official YAML Specification: The YAML 1.2.2 specification details its syntax. It defines the significance of indentation for structure and the use of '#' for comments. The case-sensitivity of keys is inherent in the definition of string equality for mapping keys.

Source: YAML Ain’t Markup Language (YAML™) Version 1.2.2 Specification, Sections 6.1 ("Indentation Spaces") and 3.2.3.3 ("Comments").

4. University Courseware: Reputable computer science courses that cover data structures and web technologies consistently teach these fundamental properties. For example, materials on data exchange formats in web programming courses highlight the case-sensitivity of JSON keys and the syntactic differences (indentation, comments) between JSON and YAML.

Source: General curriculum principles from institutions like MIT OpenCourseWare for courses on web development and data formats (e.g., 6.170 Software Studio).