JSON Validator — Check if JSON is Valid
Validate JSON syntax online. Paste your JSON and see if it is valid — detailed error messages for invalid data.
Paste your JSON and instantly see whether it is valid. Invalid JSON gets a detailed error message pinpointing the exact line and character where the syntax breaks — making debugging API responses and config files much faster.
Input JSON
Output
🔒100% Private — Your files never leave your device. All processing runs locally in your browser.
How It Works
Paste your JSON into the input panel, then click Format to pretty-print it or Minify to compress it. Invalid JSON shows a detailed error message.
The formatter uses the browser's native JSON.parse() for validation and JSON.stringify() with configurable indentation for formatting. This ensures 100% spec-compliant parsing — if something is invalid JSON, you'll know exactly where and why.
Features
- ✓Format with 2 or 4 space indentation
- ✓Minify to single line
- ✓Validate JSON and show errors
- ✓Copy formatted output
- ✓Monospace code view
Frequently Asked Questions
Missing commas, trailing commas, unquoted keys, mismatched brackets, invalid escape sequences, and more. Each error includes the line number and position.