What Is JSON? A Beginner-Friendly Guide to the JSON Format
What is JSON? This guide explains the structure of JSON (JavaScript Object Notation), the data types it supports, and where it is used in APIs, config files, and front-end/back-end communication.
JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is completely language-independent, easy for humans to read, and easy for machines to parse and generate.
JSON values come in two families. Structural types: objects are wrapped in {} (key/value pairs) and arrays in [] (ordered lists). Primitive types: strings (always double-quoted), numbers, booleans (true / false), and null.
Its most common use is as the payload of front-end/back-end APIs (e.g. a REST API returns JSON), in config files (such as package.json or tsconfig.json), and as the storage format of document databases.
Compared with XML, JSON is smaller and faster to parse; compared with YAML, it has no indentation pitfalls and is better suited for direct programmatic handling. Understanding its structure is the foundation for using any JSON tool.