JSON (JavaScript Object Notation) is a lightweight, text-based data interchange format that represents data as key-value pairs. While derived from JavaScript, it has become a language-independent universal format widely adopted across the industry.

JSON supports basic data types including strings, numbers, booleans, null, arrays, and objects. It has become the de facto standard response format for REST APIs and is indispensable in web development. Web API design books cover JSON usage patterns extensively.

JSON does not support comments, so YAML or JSON5 may be preferred for configuration files. It also lacks a date type, so datetime data is typically represented as ISO 8601 format strings.

From a character count perspective, JSON syntax elements like key names, brackets, and quotation marks affect data size. Minification removes unnecessary whitespace to reduce size. JavaScript practical guides provide additional context.