JSON Validator
Validate JSON syntax, format with proper indentation, or minify. Real-time error highlighting. [NEW-2026-06-08]
JSON Validator — Free Online JSON Checker
Validate JSON syntax instantly with real-time error detection. See the exact position of any syntax error with a caret marker and error message. Format with proper indentation at 2 spaces, or minify to a single line. Perfect for developers debugging API responses, configuration files, or data exports.
How it works
Paste any JSON into the input panel and validation runs as you type. Valid JSON is automatically pretty-printed. Invalid JSON shows the error message with the character position highlighted. Use the Format and Minify buttons to transform the output.
Developer workflow
Pair with JSON Formatter for advanced formatting options, JSON Diff to compare versions, JSON to CSV to convert to spreadsheet format, or YAML to JSON for config conversions.
Privacy & security
All validation happens in your browser. Your JSON data is never uploaded to any server.
Related: JSON Formatter, JSON to CSV, JSON Diff, XML to JSON, YAML to JSON.
FAQ
Is this tool free to use?
Yes. The tool is free to use in your browser and does not require an account.
Do I need to install anything?
No. The tool runs in a normal modern browser, so you can use it on desktop or mobile without installing extra software.
Is my data uploaded to a server?
No. All processing happens locally in your browser. Your data never leaves your device.
Can I use this for production work?
Yes, but always verify the output before using it in production. Keep a copy of your original input.
What should I check before using the result?
Review the output for accuracy, formatting, encoding, and compatibility with your target system before deploying or committing.
Does this tool work offline?
Once the page is loaded, the tool runs entirely in your browser and does not need a network connection to function.