Paste your JSON into the editor above. JSON Checker validates it instantly as you type or paste. Invalid JSON produces a clear error message with the exact line number where the problem occurs, so you can fix the JSON. Valid JSON is indented in place so you can read it. To pick the indentation, use the JSON formatter at https://jsonchecker.com/json-formatter. There is nothing to install and no button to press.

An “Unexpected token” error means the parser hit a character it wasn't expecting. The most common causes are: a trailing comma after the last item in an object or array, single quotes instead of double quotes around strings or keys, unquoted property names, a missing comma between items, or unescaped special characters inside a string. Paste your JSON above and the error message will point to the line where the parser stopped.

Start from the line number in the error message — the actual mistake is usually on that line or the one just before it. Check for missing or extra commas, mismatched brackets or braces, single quotes that should be double quotes, and unquoted keys. Fix one error at a time and re-validate; a single missing bracket can cascade into many misleading errors further down the document.