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JSON Formatter & Validator - Online JSON Beautifier

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JSON Formatter & Validator

Format, validate, beautify, and minify your JSON data instantly — free & secure

Input JSON IDLE
Formatted Output 
Formatted JSON will appear here...
Invalid JSON
Input: 0 chars Output: 0 chars Lines: 0 Size: 0 B Max Depth: -

Frequently Asked Questions

What is JSON and why should I format it?
JSON (JavaScript Object Notation) is a lightweight data-interchange format used extensively in web APIs, configuration files, and data storage. Formatting (or "beautifying") JSON makes it human-readable by adding proper indentation and line breaks, which helps developers debug, inspect, and understand complex nested data structures at a glance. Our tool transforms compressed, hard-to-read JSON into clean, structured output instantly.
How does JSON validation work?
JSON validation checks whether your text conforms to the strict JSON specification (RFC 8259). Common issues include trailing commas, missing quotes around keys, unescaped special characters, and mismatched brackets. Our validator pinpoints the exact error position and provides a clear explanation, helping you fix issues quickly. Simply paste your JSON and click "Validate" or "Format" — the tool will highlight any problems immediately.
What's the difference between "Format" and "Minify"?
Format (Beautify): Adds indentation, line breaks, and spacing to make JSON human-readable — ideal for debugging and code review.
Minify (Compress): Removes all unnecessary whitespace, producing the smallest possible valid JSON — perfect for production environments where bandwidth and storage matter. Both operations preserve the exact same data; only the presentation changes.
Is my JSON data safe and private?
Absolutely. All processing happens entirely within your browser using client-side JavaScript. Your JSON data is never uploaded to any server, transmitted over the network, or stored anywhere. You can safely format sensitive configuration files, API responses containing tokens, or proprietary data — nothing leaves your device. You can verify this by disconnecting your internet and the tool will still work perfectly.
What are the most common JSON errors and how do I fix them?
The most frequent JSON errors include:
• Trailing commas: JSON doesn't allow commas after the last item in an array or object — remove them.
• Single quotes: JSON requires double quotes for keys and string values — replace single quotes with double quotes.
• Unquoted keys: All object keys must be wrapped in double quotes.
• Comments: JSON doesn't support comments — remove any // or /* */ comments.
• Mismatched brackets: Every { must have a matching } and every [ must have a matching ]. Our tool will highlight exactly where the problem occurs.
Can I format large JSON files?
Yes! Our tool handles JSON files up to several megabytes smoothly thanks to efficient browser-based parsing. For extremely large files (10MB+), you may experience a brief processing delay depending on your device's performance. We recommend formatting large datasets in chunks if performance becomes an issue. The tool is optimized for typical use cases like API responses, configuration files, and data exports.
What indent size should I use?
It depends on your preference and project conventions:
• 2 spaces: Most popular for web development (Node.js, npm packages, VS Code default). Saves horizontal space for deeply nested structures.
• 4 spaces: Common in Python projects and some corporate standards. Provides clearer visual separation.
• Tab: Preferred by some developers for accessibility (screen readers) and personal preference. Our tool supports all three — choose what works best for your workflow.
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