JSON Validator
Validate JSON instantly and get the exact line, column and nearby snippet of any syntax error. Valid input shows structure stats: root type, keys, depth and size.
What is validated?
The tool applies the official JSON grammar (RFC 8259 as implemented by JSON.parse): strings must use double quotes, trailing commas are errors, and valid root values are objects, arrays, strings, numbers, true, false and null. On failure the parser position is translated into line/column coordinates. On success the structure summary counts every object key, the deepest nesting level and total nodes.
How to use JSON Validator
Paste the document and the validator attempts a full parse, stopping at the first syntax error with the exact line, column and an excerpt of the offending text. A clean parse means any standard JSON parser will accept the document — the guarantee you want before pasting config into production.
Common catches the validator explains: JSON has no comments, no single-quoted keys, no trailing commas and no NaN or undefined values. The position report also pinpoints mismatched brackets in long payloads, which is where manual inspection gets lost fastest.
Frequently asked questions
How exact is the error position?
The parser reports the line and column of the failure together with an excerpt of the offending text, so the fix — usually an extra comma or a missing quote — is immediately visible.
Does it validate syntax only or a schema too?
Syntax. Schema validation is a separate concern; this tool guarantees the document is well-formed JSON that any standard parser would accept.
Why does a comment make my JSON invalid?
JSON defines no comment syntax — that is JSON5 or JavaScript notation. Remove the // or /* */ comments, or keep them in a separate documentation file.
Can I validate large JSON payloads?
Yes, multi-megabyte payloads parse fine. Nothing is uploaded, so large or confidential payloads stay private on your machine either way.