JSON Validator Online
Paste your JSON and instantly know if it is valid. Get precise error messages with line numbers so you can fix issues fast.
No account required - Start instantly
Find JSON Errors Before Your Code Does
A single missing comma can break an entire API request. A trailing comma after the last element, a single quote instead of a double quote, an unescaped special character deep inside a config file. These tiny mistakes cause cryptic errors in production that take far too long to trace back to a malformed JSON string.
Our validator parses your JSON and reports exactly what is wrong and where. You get the line number, the character position, and a plain-English explanation of the problem. No guesswork. No scanning hundreds of lines by eye to find the stray bracket.
Use it for quick checks during development, for debugging failed API calls, or for verifying JSON config files before deployment. The validation runs entirely in your browser. Your data is never transmitted anywhere.
Thorough JSON Validation
Catch every kind of JSON error
Precise Error Location
Line number and character position for every syntax error found.
Human-Readable Messages
Clear explanations like 'trailing comma on line 14' instead of cryptic codes.
Common Mistake Detection
Catches trailing commas, single quotes, unquoted keys, and missing brackets.
Large File Support
Validate megabytes of JSON without slowdowns. Browser-based but powerful.
Auto-Format on Valid
Valid JSON is automatically formatted so you can inspect the structure.
Privacy First
Validation runs in your browser. No data leaves your device.
How to Validate JSON
Instant syntax checking
Paste Your JSON
Paste JSON from an API response, config file, or any source.
See the Result
Valid JSON gets a green check. Invalid JSON shows the exact error.
Fix and Re-Validate
Edit directly in the tool and validate again until it passes.