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JSON Schema Validator

Validate JSON data against a JSON Schema. Supports type, required, properties, items, enum, const, format, pattern, allOf, anyOf, oneOf, not, if/then/else, and $ref. Shows detailed validation errors with JSON paths. Runs entirely in your browser — your data never leaves your machine.

json schema validator json-schema validation draft-2020-12

Published May 29, 2026

All interactive tools run entirely in your browser. Your data never leaves your device.

How It Works

Paste your JSON data and a JSON Schema side by side. The validator instantly checks the data against the schema and reports all validation errors with their JSON paths and keywords.

Features

  • Type validation: string, number, integer, boolean, null, array, object (including type arrays)
  • String keywords: minLength, maxLength, pattern, format (email, uri, date, date-time, time, ipv4, ipv6, uuid)
  • Number keywords: minimum, maximum, exclusiveMinimum, exclusiveMaximum, multipleOf
  • Array keywords: items, minItems, maxItems, uniqueItems
  • Object keywords: required, properties, additionalProperties, patternProperties, minProperties, maxProperties
  • Composition: allOf, anyOf, oneOf, not
  • Conditional: if/then/else
  • References: $ref with JSON Pointer resolution
  • Enum / const: exact value matching
  • Error paths: each error includes the JSON Pointer path to the failing value
  • 5 examples: valid user, missing fields, array validation, nested objects, oneOf/anyOf
  • Private: runs entirely in the browser — no data transmitted

Use Cases

  • Validating API request/response payloads against a contract
  • Testing JSON Schema definitions before integrating into CI/CD
  • Debugging schema validation errors with path-level detail
  • Learning JSON Schema by experimenting with examples
  • Complementing the JSON Schema Generator tool with validation