JSON Validator

JSON has a strict, well-defined grammar — object keys must be double-quoted strings, trailing commas aren't allowed, and values are limited to strings, numbers, booleans, null, objects, and arrays. A single missing comma or an extra bracket makes the entire document unparseable, which is why a dedicated validator is useful: it runs the same parsing logic a real JSON parser would use and reports whether the document conforms, rather than leaving you to guess from a vague runtime error.

This is particularly useful when something downstream — an API client, a config loader, a test fixture — throws an unhelpful 'Unexpected token' error. Pasting the same payload here surfaces exactly where parsing breaks down, which is usually much closer to the actual mistake than the error message from whatever consumed it.

Keep in mind that syntactic validity isn't the same as being semantically correct for your use case — a JSON document can be perfectly valid JSON while still being missing a required field or having the wrong data type for your application. This tool checks structure only, not any schema your API or app expects.