JSON Formatter & Validator

JSON formatting (or beautifying) is the process of adding proper indentation and line breaks to compressed or minified JSON data, making it human-readable. This tool formats JSON with your choice of 2 spaces, 4 spaces, or tab indentation.

Paste your JSON into the input area and click "Validate". The tool will parse the JSON and report whether it's valid or show the exact error with position details. Common errors include missing commas, unquoted keys, and trailing commas.

Unexpected token errors occur when the JSON parser encounters a character it doesn't expect. Common causes include: single quotes instead of double quotes, trailing commas after the last item, comments (JSON doesn't support comments), and unquoted property names.

Yes, absolutely. This tool processes everything entirely in your browser using JavaScript. No data is ever sent to any server. Your JSON never leaves your computer, making it safe for sensitive or proprietary data.

Formatting (beautifying) adds indentation and line breaks to make JSON readable. Minifying does the opposite — it removes all unnecessary whitespace to reduce file size, which is useful for production environments and API responses.

Yes, this tool handles large JSON files efficiently in your browser. For very large files (10MB+), processing may take a moment. The tool displays file size, key count, and nesting depth statistics to help you understand your data structure.

RFC 8259 defines valid JSON as text that represents one of six structural types: objects (key-value pairs in curly braces), arrays (ordered lists in square brackets), strings (in double quotes), numbers, booleans (true/false), and null. Keys must be double-quoted strings, trailing commas are not allowed, and comments are not part of the specification. Single quotes, unquoted keys, and NaN/Infinity values are not valid JSON.

JSON formatting (beautifying) restructures valid JSON with proper indentation and line breaks for readability without changing the data. JSON validation checks whether the input conforms to the JSON specification and reports syntax errors like missing commas, unmatched brackets, or invalid characters. This tool does both — you can format valid JSON or validate it to find errors before formatting.