JSON Schema Validator — Free Online Validator
Validate JSON data against a JSON Schema
All processing happens locally. No data is sent to any server.
JSON Schema is a vocabulary that allows you to annotate and validate JSON documents. Our JSON Schema Validator checks your JSON data against a schema definition, reporting errors with precise paths so you can fix issues quickly. Paste your JSON instance on the left and your JSON Schema on the right, then click "Validate". The validator checks type constraints (string, number, boolean, object, array, null), required properties, enum values, minimum/maximum numbers, string length, and regex patterns. Each error includes the JSON path (like "address.city") so you know exactly where the problem is. This is essential for API development, configuration validation, and data quality assurance. If you're building an API that accepts JSON, you can validate sample requests against your schema to catch issues before deployment. The validator supports draft-07 schema features including type arrays, nested object validation, and array item schemas. All processing happens in your browser. Your data never leaves your device. For related tools, try our [JSON Formatter](/tools/json-formatter) to clean up your JSON before validation, or [JSON ↔ CSV](/tools/json-csv) for format conversion.
FAQ
What is JSON Schema?
JSON Schema is a vocabulary for describing the structure, constraints, and documentation of JSON data. It defines what types of values are allowed, which fields are required, and validation rules.
Which schema versions are supported?
We support core draft-07 features: type, required, properties, items, enum, minimum/maximum, minLength/maxLength, and pattern. Advanced features like $ref and oneOf are not yet supported.
Can I use this for API testing?
Yes. Define your API request/response schema and validate sample payloads to catch type errors, missing fields, and constraint violations before they reach production.