What counts as valid JSON here?

The strict specification: double-quoted keys and strings, no trailing commas, no comments, no single quotes, and no unquoted identifiers. If this tool accepts a document, a standards-compliant parser will too.

It says line 88, but line 88 looks correct.

The reported position is where parsing became impossible, which is often just after the real mistake. An unterminated string on line 80 is only detectable when the parser hits something unexpected further down. Read a little above the reported line.

Can it validate against a JSON Schema?

Not yet — this checks syntax, not shape. Schema validation is a different job and will be a separate tool.

Is it safe to paste a token or a customer record?

Yes. The document is parsed by JavaScript running in your own tab. Nothing is transmitted, so there is no server-side copy to worry about.

JSON Validator

Check JSON is valid and get the line and column of the fault.

Everything runs inside your browser. Your files never leave your device.

Input

Result

The result appears here as you type.

Ask about JSON Validator

Questions about what this tool does, which option to pick, or what it can and cannot handle.

This is the one part of the site that uses a server. The question you type here is sent to an AI provider to be answered — your files and whatever you put in the tool above are not, and the assistant cannot see them. Answers are generated and can be wrong; the tool itself is not guessing.

About the JSON Validator

A validator answers one question — will a parser accept this? — and, when the answer is no, says exactly where it stopped. That is most of the value. Malformed JSON almost always fails at a single identifiable character, and the difference between a five-second fix and a twenty-minute hunt is knowing which character.

This validator reports the line and column of the first fault. It finds that position itself by scanning the document, rather than relying on the browser's error message, because those messages vary wildly between browsers and versions — some give a byte offset, some give a truncated excerpt and no position at all.

When the document is valid, the tool describes its shape instead: the root type, how many objects and arrays it contains, the total number of keys, how many scalar values there are and how deeply the structure nests. That summary is a quick sanity check against what you expected. An API that should return a list of twenty items and reports one object at depth two has told you something useful before you have read a single field.

Everything happens in your browser. You can validate a payload containing real customer data or a live token without it leaving the machine.

How to use it

1Paste the JSON you want to check into the input box.
2Read the verdict below: either a confirmation with a structure summary, or an error naming the line and column.
3Fix the reported position in your source and paste it again — the check reruns as you type.
4Turn off “Show a structure summary” if you only want the pass or fail.

Questions

What counts as valid JSON here?: The strict specification: double-quoted keys and strings, no trailing commas, no comments, no single quotes, and no unquoted identifiers. If this tool accepts a document, a standards-compliant parser will too.
It says line 88, but line 88 looks correct.: The reported position is where parsing became impossible, which is often just after the real mistake. An unterminated string on line 80 is only detectable when the parser hits something unexpected further down. Read a little above the reported line.
Can it validate against a JSON Schema?: Not yet — this checks syntax, not shape. Schema validation is a different job and will be a separate tool.
Is it safe to paste a token or a customer record?: Yes. The document is parsed by JavaScript running in your own tab. Nothing is transmitted, so there is no server-side copy to worry about.