JSON Formatter

Format and beautify JSON data with syntax highlighting.

How to Use

  1. Paste your raw or minified JSON into the input field on the left.
  2. Select your preferred indent size (1, 2, 3, or 4 spaces, or tab) and JSON specification.
  3. Click 'Format / Beautify' to format, or 'Minify' to compress.
  4. Copy the formatted output or download it as a file.
  5. Use the batch tab to upload and process multiple JSON files or a ZIP archive at once.

Features

  1. Format and beautify JSON with configurable indent sizes
  2. Minify JSON to reduce file size
  3. Validate against RFC 8259, RFC 7159, RFC 4627, and ECMA-404 specifications
  4. Batch processing — upload multiple JSON files or a ZIP archive
  5. Download formatted results as individual files or a ZIP
  6. 100% client-side — your data never leaves your browser

FAQs

What is JSON formatting?

JSON formatting (or beautifying) adds proper indentation, line breaks, and spacing to a raw JSON string, making it much easier to read and debug.

Is my data safe?

Absolutely. All processing happens directly in your browser. Your JSON data never leaves your device — nothing is sent to any server.

Can I validate JSON here?

Yes! The tool automatically validates your JSON as you type. If there are syntax errors, you'll see a detailed error message indicating the problem.

What's the maximum size?

Since processing happens in your browser, the limit depends on your device's memory. Most devices handle several megabytes of JSON without issues.

Technical Details

Formatting JSON requires parsing the raw string through JavaScript's native JSON.parse() to validate syntax and construct an in-memory object tree. The tool then serializes this object back into a string using JSON.stringify() with specific spacing parameters (typically 2 or 4 spaces) that control indentation depth. During stringify, the algorithm recursively traverses nested objects and arrays, injecting newlines and whitespace according to the configured indent level to create the human-readable columnar layout. Syntax highlighting is applied post-format by wrapping keys, strings, numbers, and booleans in HTML spans with corresponding CSS color classes.