JSON Validator

Validating JSON usually means one of two very different things. The JSON Formatter checks that a document is syntactically valid — braces balanced, commas in the right places, strings properly quoted. This tool checks something deeper: whether a document's actual content matches a set of rules you define — a JSON Schema — covering required fields, value types, numeric ranges, string patterns, and more.

That distinction matters in practice: a payload can be perfectly valid JSON and still be the wrong shape for what your application expects — a missing required field, a price that's negative, an email that isn't actually an email. This tool checks both a JSON Schema and a document against each other, using the same JSON Schema standard the Schema Generator tool produces, and reports every rule that failed with the exact path to the offending field. Everything runs locally in your browser.

• •Don't hand-write a schema from scratch if you already have a representative payload — generate a starting point with the JSON Schema Generator, then tighten it here.
• •allErrors is always on here, so you'll see every rule that failed at once, not just the first one — useful for fixing a payload in one pass instead of one error at a time.
• •A schema with a typo in a keyword (e.g. "required" spelled wrong) won't necessarily error loudly — unknown keywords are usually just ignored by JSON Schema validators, so double-check keyword spelling if a constraint doesn't seem to be enforced.
• •String format checks ("email", "date-time", "uuid", etc.) validate the shape of the string, not that the value is real — an email format check will accept a syntactically valid but non-existent address.