JSON Schema Validator

About the JSON Schema validator

A JSON Schema describes the shape a document is allowed to take — required fields, value types, string formats, array rules — and validators enforce it. This tool runs a document through a schema entirely in your browser and reports not just pass/fail but every individual violation, with the tree path to the offending value so you can go straight to it. No upload, no server round-trip.

Draft 2020-12 support

The validator covers the subset that appears in everyday schemas: type(with integer distinct from number),properties, required,additionalProperties, itemsand tuple prefixItems, enum /const, composition keywords (anyOf, allOf,oneOf, not), numeric bounds, string length/pattern/format, and array cardinality plusuniqueItems. Supported formats include email, URI, UUID, date-time, IPv4, and hostname.

Reading the output

Each error shows a $-prefixed path in the same dot/bracket notation the formatter tree uses (e.g. $.contact.email), followed by a reason such as Missing required property or Expected string, got number. Complex schemas like anyOf are judged against the whole alternative set, so you get one clear outcome per value rather than a cascade. The report can be copied or downloaded for your CI-style workflow.

Related tools

Need a schema to start from? Generate one from an example with the JSON Schema generator, tidy documents before validating with the JSON formatter, or check two versions against each other with the JSON diff tool.