JSON Schema Validator
Draft-07Paste a JSON Schema (Draft-07) and your JSON data to validate structure, types, required fields, and constraints — with per-field error reporting. Runs entirely in your browser.
What Is JSON Schema Validation?
JSON Schema validation is the process of checking a JSON document against a formal specification called a JSON Schema. The schema defines the expected shape of the data — which fields should exist, what types they should be, what values are acceptable, and whether additional fields are allowed. It acts like a contract for your data.
JSON Schema is a W3C-adjacent standard used extensively in OpenAPI/Swagger specs, MongoDB document validation, Kubernetes CRD definitions, VSCode settings, and API request/response validation (via libraries like Ajv, Zod, and Joi).
Supported Keywords
type— string, number, integer, boolean, array, object, nullproperties/requiredadditionalPropertiesitems,minItems,maxItemsminLength/maxLengthminimum/maximumenum,constpattern,formatanyOf,oneOf,allOf,not$ref(local definitions)uniqueItems,multipleOfminProperties/maxProperties
Why Not Just Use AI?
AI chatbots often miss subtle schema violations — they may skip additionalProperties checks, misinterpret oneOf vs anyOf, or hallucinate that a value is valid when it isn't. This tool applies each constraint algorithmically with zero ambiguity, giving you deterministic results that match what runtime validators like Ajv produce.
JSON Schema Validator FAQs
JSON Schema is a vocabulary that allows you to annotate and validate JSON documents. It defines the expected structure, data types, required fields, and constraints of a JSON object. It's widely used for API request/response validation, configuration file validation, and database document validation.
This tool supports JSON Schema Draft-07 semantics, covering all major keywords: type, properties, required, additionalProperties, items, minLength/maxLength, minimum/maximum, pattern, enum, const, anyOf, oneOf, allOf, not, $ref (local definitions), and common format validators (email, uri, date, date-time).
No. All validation runs entirely in your browser using JavaScript. Your JSON schema and data are never uploaded to any server. This tool is 100% client-side and works offline.
Each validation error shows three things: the JSON path to the failing field (e.g., #.address.country), the keyword that failed (e.g., minLength, required, type), and a human-readable message explaining what constraint was violated.
Yes. Local $ref references (those pointing to definitions within the same schema, e.g., #/definitions/Address) are fully supported. External URL-based $refs are not supported since the tool is offline-first.
AI chatbots cannot reliably validate JSON against a schema — they might miss constraint violations or hallucinate rules. This tool deterministically applies every schema keyword, giving you guaranteed, exact, reproducible results every time.