Tiny Toolkit

JSON Validator — Check & Verify JSON Syntax Free

Paste JSON to instantly check whether it is syntactically valid, with a clear error message and approximate line number if it is not. Valid JSON also shows its root type, maximum nesting depth, and total key count for a quick structural overview. Useful before committing config files, debugging API responses, or feeding data into a JSON Schema validator.

All processing happens in your browser. No data is sent to any server.

Frequently Asked Questions

What does the JSON validator check?
It checks that your JSON is syntactically valid and pinpoints the exact line and column of any error. For valid JSON it also reports the root type, maximum nesting depth, and key count.
Does it validate against a JSON Schema?
Not currently. It validates syntax only, not against a schema definition.
Can it validate minified JSON?
Yes. The validator accepts both pretty-printed and minified JSON.
What does 'Total keys' count?
Total keys counts all property names across every object in the document, at every nesting level. For example, {"a": {"b": 1}} has 2 total keys ("a" and "b"). This gives a sense of overall document complexity, not just the top-level structure.

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