DevToolKit

JSON Schema Validator — Validate Data Against a Schema [2026]

Validate JSON data against a JSON Schema. See all validation errors at once with paths and details. Supports Draft-07 features. Free, browser-based, no signup.

What is JSON Schema Validator?

JSON Schema Validator is a free online tool that checks whether a JSON document conforms to a JSON Schema definition. JSON Schema is a standard for describing the structure and constraints of JSON data, including required fields, data types, string patterns, numeric ranges, and more.

How to Use JSON Schema Validator

Paste your JSON Schema in the left panel and the JSON data you want to validate in the right panel. Click "Validate" or just edit either panel — validation runs automatically. The tool shows all validation errors with the property path, error message, and expected vs. actual values.

How JSON Schema Validator Works

The tool uses the Ajv (Another JSON Schema Validator) library compiled for the browser. It supports JSON Schema Draft-07 features including type validation, required properties, pattern matching, minimum/maximum constraints, enum values, allOf/anyOf/oneOf, and $ref references within the same schema.

Common Use Cases

  • Validating API request/response payloads against a schema
  • Testing JSON Schema definitions before adding them to code
  • Debugging schema validation failures in CI/CD pipelines
  • Learning JSON Schema syntax with instant feedback
  • Checking configuration files against a specification

Frequently Asked Questions

Which JSON Schema version does this tool support?

It supports JSON Schema Draft-07, which is the most widely used version. This includes all common keywords like type, required, properties, items, pattern, minimum, maximum, enum, allOf, anyOf, oneOf, and more.

Can it validate nested objects and arrays?

Yes. The validator fully supports nested object schemas with properties and additionalProperties, array schemas with items and minItems/maxItems, and recursive structures.

What error information does it show?

Each error includes the JSON path to the invalid property (e.g., /users/0/email), the validation keyword that failed, and a human-readable message explaining what went wrong.

Is my data secure?

Yes. All validation is performed in your browser. No data is transmitted to any server.

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