JSON Formatter & Validator

JSON (JavaScript Object Notation) is a lightweight, human-readable data interchange format. It is the de facto standard for web APIs, configuration files, and data exchange between applications. It supports strings, numbers, booleans, null, arrays, and objects.

Formatting (or "pretty print") adds indentation and line breaks to compact JSON to make it readable. This tool uses standard 2 or 4 space indentation. Minification does the opposite: removes all unnecessary whitespace to reduce file size.

Yes, completely. All parsing and formatting happens in your browser using native JSON.parse() and JSON.stringify(). No data is ever sent to external servers.

Valid JSON must follow strict rules: keys must be double-quoted strings, no trailing commas, no comments, no undefined values. Common errors include: single quotes instead of double, comma after the last element, NaN or Infinity as values.

Yes, the tool handles JSON files up to several MB directly in the browser. For very large files (>10MB), performance depends on your device. Processing is entirely local, so there are no upload limits.