Struggling to read messy JSON? Our free Online JSON Formatter beautifies raw JSON instantly – adding indentation and color highlights so you can actually read it. Paste your JSON and get a clear, error-checked output in seconds. (Bonus: it even sorts object keys alphabetically for consistency!)
Format, validate, and beautify your JSON with this easy-to-use tool
Input JSON
Formatted Output
Why Use A JSON Formatter Tool?
- Human-readability (indentation and line breaks make JSON easier to understand).
- Easier debugging (errors stand out when JSON is properly formatted).
- Save time instead of trying to format with manualy written code.
- Secure and can workoffline once loaded. Runs in your browser, so your data isn’t sent to a server.
JSON Formatter Features:
- Pretty-print:
- Beautify/Formats JSON data with proper indentation
- Key Sorting(Optional configurable)
- By object keys alphabetically for consistent output
- Validation
- Validate JSON syntax with detailed error messages
- Error highlighting for invalid JSON with specific error details
- Auto Fix
- Auto-fix common JSON errors (enabled by default)
- Copy to clipboard / Download
- Copy formatted output to clipboard with confirmation.
- Download the formatted output as a “.json” file to your local computer.
- Syntax highlighting
- Colour-coded key/values for better readability
- Tree Node Expand/Collapse:
- Click toggle buttons (+/–) to expand/collapse JSON nodes
- Expand/Collapse nested objects and arrays
- The state is preserved during formatting
- Parent nodes can be collapsed to hide all children
- Size Comparison:
- Real-time size updates on input changes
- Supports multiple units (bytes, KB, MB, GB)
- Accurate to 2 decimal places
- Updates automatically when formatting or editing
How to Format JSON (Step-by-Step):
- Enter JSON Data
Paste your JSON string into the input area. Or use the “Load Sample” button if you are just trying out the tool.
- (Optional) Update Configuration
Toggle “Auto fix” checkbox to enable/disable automatic error correction. Toggle “Sort keys” checkbox to enable/disable sorting of keys.
- Validate and Format
Click “Format JSON” to validate and format. The tool will automatically validate the JSON syntax. If valid, it will be formatted with proper indentation.
- Copy formatted JSON
Click “Copy Output” button. A confirmation message will appear when copied successfully
- Error Handling
The error message will indicate the issue. The input area will be preserved for corrections.
Example Input
{"z":1,"a":{"d":2,"c":3},"b":[4,3,2]}
Code language: JSON / JSON with Comments (json)Example Output
JSON Formatter Current Limitations
- Large JSON files may impact performance
- The tool currently does not sort array elements (only sorts the object keys)
- Clipboard operations require secure context (HTTPS or localhost)
- Does not preserve trailing commas
- Unicode characters in strings are not escaped/unescaped
- No support for JSON5 or JSON with comments (JSONC)
- The auto-fix feature is not a full JSON5 parser and may not fix all syntax errors.
Error Handling
- This JSON Formatter Tool provides specific error messages for common JSON syntax errors:
- Missing or extra commas
- Unclosed brackets or braces
- Invalid property names
- Missing colons
- Invalid values
- You will see any errors below the input area
- The error message includes the position where it detected the error
Privacy & Security
- 🔒 100% Client-Side Processing: All JSON formatting and validation happens in your browser
- 🚫 No Server Storage: Your JSON data is never saved or transmitted to any server
- 💻 Offline Support: Fully functional without an internet connection once loaded
- 🔐 Zero Data Collection: No cookies, tracking, or data persistence of any kind
Browser Support
- Modern Browsers: Chrome, Firefox, Safari, Edge
- Requirements:
- JavaScript enabled
- For copy functionality:
- Primary: Modern Clipboard API (secure context – HTTPS or localhost)
- Fallback: execCommand (older browsers/HTTP contexts)
- Mobile Support: Fully responsive design with touch-friendly controls
Feedback:
Please contact us for any bug report/feature request/feedback.
JSON Formatter FAQs:
A JSON Formatter is an online tool that takes unformatted or minified JSON data and beautifies it by adding proper indentation and line breaks. This makes the JSON much easier for humans to read and debug.
To pretty-print JSON, you can use an online JSON Formatter. Simply paste your JSON and click the format button. The tool will output a nicely indented JSON structure with sorted keys and highlighted syntax for easy reading.
Yes – as long as the formatter runs in your browser (client-side), your JSON data isn’t sent anywhere, making it safe. The CodeSamplez JSON Formatter Tool processes JSON locally, so your sensitive data never leaves your computer.
Yes, this JSON Formatter also acts as a validator. If your JSON has a syntax error (like a missing comma or quote), the tool will alert you and pinpoint the error so you can fix it and format again.