JSON (JavaScript Object Notation)

A lightweight data-interchange format that is easy for humans to read and write, and easy for machines to parse and generate.

JSON (JavaScript Object Notation) is a lightweight, text-based data interchange format that is easy for humans to read and write, and easy for machines to parse and generate. Although derived from JavaScript object syntax, JSON is language-independent and supported by virtually all modern programming languages.

JSON represents data as key-value pairs (objects) and ordered lists (arrays). Supported data types include strings, numbers, booleans, null, objects, and arrays. Its simplicity and readability have made it the dominant format for API request and response bodies, configuration files, and data storage in document databases.

In API development, JSON is the standard payload format for REST and GraphQL APIs. API gateways frequently work with JSON data for request validation (checking that incoming payloads match expected schemas), response transformation (reshaping data before returning it to clients), and logging. Many API specification formats, including OpenAPI, can be written in JSON. Serverless function inputs and outputs are also typically JSON-encoded.