JSON (JavaScript Object Notation) is a lightweight, human-readable data format used for storing and exchanging structured data. It uses key-value pairs and nested arrays to represent complex information in a text format that both humans and machines can easily parse.

JSON is the standard format for REST APIs, configuration files (package.json, tsconfig.json), and data interchange between services. Nearly every programming language has built-in JSON support, making it the universal language of modern web development.

Validating JSON before use catches syntax errors like missing commas, trailing commas (not allowed in strict JSON), unquoted keys, or mismatched brackets. This tool highlights errors with exact line and column positions, and provides syntax highlighting so you can quickly spot structural issues. Everything runs client-side — your data never leaves your device.