JSON Formatter
Format and validate JSON
This free online json formatter runs in your browser and is part of our Developer Tools collection.
JSON Formatter
Format, validate, and beautify JSON data. Supports minification and syntax highlighting.
Features:
- Automatic JSON validation with error messages
- Beautify with custom indentation (2 or 4 spaces)
- Minify JSON for production use
- Syntax highlighting for easier reading
- Error line number indication
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Instant In-Browser Execution
Runs locally in JavaScript without wait times or server delays.
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100% Privacy & Security
Your inputs and files are never stored or logged on remote servers.
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Cross-Device Responsive
Fully optimized for mobile smartphones, tablets, and desktop displays.
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100% Free Forever
No subscription fees, no signups, and no software installations.
How to Use the Online JSON Formatter
1
Paste or Upload JSON
Paste your raw or minified JSON payload into the input editor, or drag-and-drop a `.json` file.
2
Choose Indentation & Sort Keys
Select 2 spaces, 4 spaces, or Tabs for pretty-printing, and optionally toggle "Sort Keys Alphabetically".
3
Validate & Format Syntax
Click "Format" to pretty-print or "Minify" to remove whitespace; syntax errors highlight line numbers and error tokens instantly.
4
Copy Clean JSON or Download
Click "Copy" to save to clipboard or download as a formatted `.json` file.
Frequently Asked Questions
Common questions about using this free online json formatter.
Is my confidential JSON data uploaded to an external server? ▾
No. All parsing, validation, and pretty-printing occur strictly inside your web browser via client-side JavaScript. Your API payloads and customer data never leave your computer.
What causes the most common JSON syntax errors? ▾
The most frequent errors are trailing commas after the final object key or array element, unquoted keys, single quotes instead of double quotes, and unescaped control characters.
What does the "Sort Keys" feature do? ▾
It recursively sorts all dictionary object keys alphabetically, making it effortless to compare two API responses or inspect deeply nested payloads.
Can this tool handle massive JSON files? ▾
Yes. It can process multi-megabyte JSON payloads in memory in milliseconds without UI freezes.
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