That JSON error, translated into plain language.
Paste a URL or a blob of JSON. Whatsjson parses it and, when parsing fails, points at the exact line and column and says what was expected there in plain English — not "unexpected token at position 4471."
How it works
Two ways to get a clear answer about what broke and why.
Paste a URL
Enter an API endpoint URL. Whatsjson fetches it and inspects the response — the content-type, whether the body is JSON at all, and whether a JSON error object is dressed as a success.
Or paste JSON directly
Paste a blob of JSON into the text area. Parsing happens entirely in your browser — nothing is sent anywhere.
Read the diagnostic
A human-readable breakdown of what went wrong, where, and what was expected instead. No jargon, no mystery position numbers.
What you get
More than a parse error — a full picture of what the server actually sent.
Exact error location
Line and column — not a character offset. Whatsjson tells you where the problem is and shows context from surrounding lines.
Plain-English explanation
No cryptic messages. "Trailing comma after the last value is not allowed" instead of "unexpected token at position 4471."
Error-object detection
Many APIs return a 200 status with an error body. Whatsjson detects error fields, success: false, and other disguised failures.
Server response analysis
See what the server actually sent: content-type, body length, status code, and a reliability flag for the diagnostic.
Start debugging your JSON in seconds.
No registration required. No data leaves your browser unless you check a URL.
Open the tool