Schema Validator - Free Online Tool | PivaBox

Validate JSON against JSON Schema rules

Schema Validator — Validate JSON Data Against JSON Schema, OpenAPI, and More

  1. Paste your JSON data in the left panel and your schema definition in the right panel. The validator supports JSON Schema (Draft 4/6/7/2020-12), OpenAPI 3.x schemas, and Swagger 2.0 definitions.
  2. The validator instantly checks your data against the schema and reports: validation errors with exact paths (e.g., "$.user.address.zipCode: expected string, got number"), missing required fields, type mismatches, pattern violations, enum constraint failures, and more. Errors link directly to the relevant line in your data.
  3. Fix validation errors iteratively. The validator provides human-readable error messages and suggestions for common issues. Use it to validate API payloads, configuration files, data imports, or any JSON that must conform to a specification.

Frequently Asked Questions

Is the Schema Validator free?

Yes, completely free. Validate unlimited documents against your schemas — essential for API development, data quality assurance, and CI/CD pipelines.

Are my JSON data and schemas uploaded anywhere?

No. All validation is performed locally in your browser. Your data, API schemas, and validation results stay private on your device.

What is JSON Schema and how do I write effective schemas?

JSON Schema is a vocabulary that allows you to annotate and validate JSON documents. It defines: (1) Required fields — which properties must be present. (2) Types — string, number, integer, boolean, array, object, null. (3) Constraints — minimum/maximum values, string patterns (regex), string lengths, array lengths, enum values. (4) Nested schemas — objects within objects, arrays of typed items. (5) Conditionals — if/then/else logic for complex validation rules. Example schema: {"type": "object", "required": ["name", "email"], "properties": {"name": {"type": "string", "minLength": 1}, "email": {"type": "string", "format": "email"}, "age": {"type": "integer", "minimum": 0, "maximum": 150}}}. JSON Schema is used by OpenAPI/Swagger for API documentation, by MongoDB for collection validation, by AWS CloudFormation and Terraform for infrastructure-as-code, and by most API gateways for request validation. Use $ref to compose large schemas from reusable components.