JSON (JavaScript Object Notation) is the most widely used format for APIs, config files, and data storage. Unformatted JSON is difficult to read, and invalid JSON causes errors. This tool formats JSON with proper indentation, validates structure with clear error messages, and minifies to reduce file size.
Paste unformatted or minified JSON into the input field. The tool validates the syntax and displays it with proper indentation. If the JSON is invalid, an error message shows the exact position and nature of the problem. Use Format to pretty-print or Minify to compress JSON by removing all whitespace.
JSON formatting is essential for debugging API responses in web development, reading configuration files (package.json, tsconfig.json), inspecting data stored in databases and caches, preparing JSON payloads for API testing tools, validating JSON before sending it to endpoints, comparing JSON structures during code reviews, and creating readable documentation that includes JSON examples.
The formatter uses JSON.parse() for validation - which provides exact error positions for malformed input - followed by JSON.stringify(data, null, indent) for formatting. Minification uses JSON.stringify(data) without indentation. Syntax highlighting is applied using regex-based tokenization that identifies strings, numbers, booleans, null values, keys, and structural characters. The tool handles all valid JSON types: objects, arrays, strings, numbers, booleans, and null.
Paste your JSON into the input field. The tool automatically validates the structure and displays it with proper indentation (2 or 4 spaces) and syntax highlighting. Invalid JSON shows a clear error message with the line and character position.
Click the 'Minify' button to remove all whitespace, newlines, and indentation from the JSON. This reduces file size for production use - minified JSON can be 30-60% smaller than formatted JSON.
Common JSON errors include: trailing commas after the last item, single quotes instead of double quotes, unquoted property names, missing commas between items, and comments (JSON does not support comments).
JSON is a strict subset of JavaScript. JSON requires double-quoted property names, doesn't allow trailing commas, doesn't support comments, undefined, or functions. All valid JSON is valid JavaScript, but not all JavaScript objects are valid JSON.
Transform, format, generate, and encode data instantly. Private, fast, and always free.
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