Which JSON Schema keywords are supported?

Core validation keywords across draft-07 and 2020-12: type, required, properties, additionalProperties, items, enum, const, minimum, maximum, exclusiveMinimum, exclusiveMaximum, minLength, maxLength, pattern, minItems, maxItems, uniqueItems, minProperties, maxProperties, and the combinators allOf, anyOf, oneOf, and not.

What is a JSON Pointer path?

It is a slash-separated path to the failing location, like /address/zip or /tags/2. The empty pointer refers to the root document. This makes it easy to find exactly which field in a large document failed.

Does it fetch remote schema references?

No. To keep validation fully offline and private, external $ref URLs are not fetched. Local references within the same schema are not resolved either, so inline your schema for full validation.

How are types checked?

The type keyword accepts a single type or an array of allowed types. Note that integer requires a whole number, number accepts any numeric value, and arrays and null are distinguished from object, matching the JSON Schema type model rather than JavaScript typeof.

No. Both the schema and the document are validated entirely in your browser. Neither is transmitted to any server, so confidential payloads stay private.

JSON Schema Validator

JSON Schema Validator checks whether a JSON document conforms to a JSON Schema and pinpoints every failure. Instead of a single pass/fail, it lists each violation with a JSON Pointer path and a human-readable reason, so debugging a large payload is quick. It implements the core validation keywords shared by draft-07 and draft 2020-12, and runs entirely in your browser.

How it works

Validation walks the schema and the data together, starting at the root with the JSON Pointer "". At each node the validator applies the keywords present in the schema:

type / enum / const — checks the value’s JSON type or membership in a fixed set.
Numeric — minimum, maximum, exclusiveMinimum, exclusiveMaximum.
String — minLength, maxLength, and pattern (a regular expression).
Object — required, properties, additionalProperties, minProperties, maxProperties. Each property recurses with its key appended to the pointer.
Array — items (applied to every element, with the index appended to the pointer), minItems, maxItems, uniqueItems.
Combinators — allOf, anyOf, oneOf, and not aggregate sub-results.

Every failure pushes an entry holding the pointer and the reason, and the collected list is shown at the end.

Tips and notes

Because the validator does not fetch remote $ref targets, inline the full schema for complete coverage — this keeps the tool offline and your data private. The type keyword follows the JSON model: integer demands a whole number, null is its own type, and arrays are not objects. Try the bundled example, then tweak the document to see the pointer paths update as new errors appear.