JSON Schema Validator

How to Use

1. Enter or paste your JSON Schema in the left panel.
2. Enter or paste the JSON data to validate in the right panel.
3. Validation runs automatically as you type — or click Validate.
4. View errors with JSON paths showing exactly where validation fails.

What Is JSON Schema?

JSON Schema is a declarative language for defining the structure and constraints of JSON data. It acts as a contract between systems — if your API says it returns a certain shape of JSON, the schema defines exactly what that shape looks like. Schemas can specify data types, required fields, string patterns, numeric ranges, array lengths, and nested object structures.

Common Schema Keywords

• type — The data type: string, number, integer, boolean, array, object, or null
• required — Array of property names that must be present
• properties — Define schemas for each property of an object
• items — Schema for array elements
• enum — Restrict values to a specific set
• minLength / maxLength — String length constraints
• minimum / maximum — Numeric range constraints
• pattern — Regex pattern for string validation
• additionalProperties — Whether unknown properties are allowed

Use Cases for JSON Schema

JSON Schema is used for API request/response validation, configuration file validation, form generation, code generation (TypeScript interfaces from schemas), and documentation. Tools like Ajv, OpenAPI, and many API gateways use JSON Schema for runtime validation.

Related Tools

Format JSON data with the JSON Formatter. Validate JSON syntax with the JSON Validator. Generate TypeScript types from JSON with JSON to TypeScript. Convert between JSON and YAML with the JSON-YAML Converter. Generate TypeScript from OpenAPI schemas with OpenAPI to TypeScript. View validated data in the CSV Viewer. Generate test data with the Mock Data Generator.