JSON Formatter & Validator Online
Format, validate and beautify JSON data online
Press Ctrl+Enter to format
How to Use JSON Formatter & Validator Online
- 1Paste or type your JSON data into the input textarea.
- 2Click "Format" to beautify with indentation, "Minify" to compress, or "Validate" to check syntax.
- 3Choose your preferred indentation (2 or 4 spaces).
- 4Use the Copy button to copy the formatted output to your clipboard.
About JSON Formatter & Validator Online
Format, validate and beautify your JSON data online for free with syntax highlighting, line numbers and dark mode support. Paste your JSON and instantly get a clean, readable output — no signup required. This tool parses your JSON string, checks for syntax errors, and re-formats it with proper indentation entirely in your browser.
Frequently Asked Questions
Is my JSON data sent to a server?
No. All formatting and validation happens locally using JavaScript.
What JSON errors does this tool detect?
It detects all standard JSON syntax errors including missing commas, unmatched brackets, invalid strings, trailing commas and incorrect data types.
Can I format large JSON files?
Yes. The formatter handles JSON files of several megabytes. For extremely large files (50MB+), performance may vary depending on your browser and device.