JSON Validator
Paste your JSON data below to instantly check for syntax errors and ensure it is strictly well-formed.
How To Validate JSON
Paste Code
Copy your JSON string from your file or API response and paste it directly into the editor box.
Auto-Check
Click "Validate JSON". The tool parses the structure to identify any missing brackets, quotes, or commas.
View Results
Instantly see if your JSON is valid. If there are errors, a specific message will tell you exactly what went wrong.
Key Features
Detailed Error Reporting
Finds syntax errors like trailing commas, missing quotes, or unclosed braces and displays the specific error message from the parser.
Instant Client-Side Validation
The entire validation process happens in your browser using native JavaScript, ensuring zero latency and maximum speed.
Secure & Private
Your data never leaves your device. Since no data is sent to a server, your sensitive configuration files and API keys remain completely private.
Frequently Asked Questions
Common errors include trailing commas after the last item in a list (which is allowed in JS but not JSON), using single quotes instead of double quotes for strings, and missing quotes around property keys.
This tool checks for syntactic validity (is it well-formed JSON?). It does not validate against a specific custom schema. For that, you would need a Schema Validator.
JSON is stricter than JavaScript objects. Keys must be double-quoted (e.g., "key": not key:), and values cannot be functions, undefined, or comments. Ensure you are following strict JSON standards.
Since the validation happens in your browser, the limit depends on your computer's memory (RAM) and browser capabilities. It can generally handle very large files (several megabytes) without issues.
No. The official JSON standard (RFC 8259) does not support comments (`//` or `/* */`). If your file contains comments, this validator will flag it as invalid.
Yes, completely. We do not store or transmit your code. All processing is done locally within your browser using JavaScript's native JSON.parse() method.