What this validator checks
This tool parses your input with the browser's native JSON.parse and reports whether it is strictly valid JSON per the JSON specification. On failure, it points to the exact line and column where parsing broke.
Valid JSON vs. valid JavaScript object
JSON is stricter than a JavaScript object literal: keys must be double-quoted strings, trailing commas are not allowed, and values are limited to strings, numbers, booleans,null, objects and arrays — no functions, comments, or undefined. A lot of "invalid JSON" reports come from pasting JS object literals that rely on this looser syntax.
FAQ
Why does it say my JSON is invalid when it looks fine?
Common culprits: a trailing comma before } or ], single quotes instead of double quotes, or an unescaped double quote inside a string. Check the reported line/column — the error is usually right there or on the token just before it.
Is my data uploaded anywhere?
No — validation runs entirely in your browser.