JSON Validator
Paste or upload JSON to instantly check whether it is valid. Get the exact line, column and reason for any syntax error. Everything runs locally in your browser — no data leaves your device.
Input JSON
0 chars · 0 lines
Result
Waiting for input…
Start typing or paste some JSON — it validates as you type.
What this JSON validator checks
Syntax
Confirms the document parses as strict, RFC 8259 JSON.
Error location
Pinpoints the exact line and column where parsing failed.
Reason
Shows the parser's message — trailing comma, unquoted key, and so on.
Structure
Reports the root type, key/element count and nesting depth.
Size
Counts characters, lines and the byte size of your JSON.
Private
Runs entirely in your browser — nothing is uploaded.