Is my data sent to a server?

No. All schema generation and validation runs 100% in your browser. Your JSON data never leaves your device.

JSON Schema is a vocabulary for annotating and validating JSON documents. It defines the structure, data types, required fields, and constraints of a JSON object. It is used for API documentation (OpenAPI), form validation, configuration validation, and data contracts.

What is the difference between JSON Schema draft-07 and draft-2020-12?

Draft-2020-12 is the latest version with improved support for dynamic references, unevaluatedProperties, and prefixItems for tuple validation. Draft-07 is the most widely supported version — used by most validators, code generators, and OpenAPI 3.0. Use draft-07 for maximum compatibility.

Can I validate JSON against a schema?

Yes. Paste your JSON Schema in the schema panel and your JSON data in the data panel. The tool validates the data against the schema and shows all validation errors with JSON Pointer paths to the failing fields.

Can I generate a schema from a TypeScript interface?

Yes. The TypeScript tab converts TypeScript interface definitions to JSON Schema. This is useful for generating API documentation schemas from your existing TypeScript types.

JSON Schema Generator

Generate JSON Schema from JSON, TypeScript interfaces, or wrap into OpenAPI 3.0.

JSON Input

Generated Schema

{
  "type": "object",
  "properties": {
    "id": {
      "type": "integer",
      "examples": [
        1
      ]
    },
    "name": {
      "type": "string",
      "examples": [
        "Alice Smith"
      ],
      "minLength": 1
    },
    "email": {
      "type": "string",
      "examples": [
        "alice@example.com"
      ],
      "format": "email",
      "minLength": 1
    },
    "age": {
      "type": "integer",
      "examples": [
        30
      ]
    },
    "active": {
      "type": "boolean",
      "examples": [
        true
      ]
    },
    "score": {
      "type": "number",
      "examples": [
        9.5
      ]
    },
    "tags": {
      "type": "array",
      "items": {
        "type": "string",
        "examples": [
          "admin"
        ],
        "minLength": 1
      }
    },
    "address": {
      "type": "object",
      "properties": {
        "city": {
          "type": "string",
          "examples": [
            "New York"
          ],
          "minLength": 1
        },
        "zip": {
          "type": "string",
          "examples": [
            "10001"
          ],
          "minLength": 1
        }
      },
      "required": [
        "city",
        "zip"
      ]
    }
  },
  "required": [
    "id",
    "name",
    "email",
    "age",
    "active",
    "score",
    "tags",
    "address"
  ],
  "$schema": "http://json-schema.org/draft-07/schema#"
}

About the JSON Schema Generator

JSON Schema is the standard way to define the structure and constraints of JSON data — used in OpenAPI specifications, form validation, configuration files, and data contracts between services. Writing schemas by hand is tedious for complex nested structures. This tool generates JSON Schema from a JSON sample, validates JSON against a schema, and converts TypeScript interfaces to JSON Schema.

What this tool does

Schema Generation

Generates a JSON Schema from any JSON sample. Infers types, required fields, and nested object structures automatically.

JSON Validation

Validates JSON data against a schema and shows all errors with JSON Pointer paths — pinpoints exactly which fields fail which constraints.

TypeScript → Schema

Converts TypeScript interface definitions to JSON Schema — useful for generating OpenAPI schemas from existing TypeScript types.

OpenAPI Wrapper

Wraps the generated schema in an OpenAPI 3.0 component definition — ready to paste into your API specification.

Pipeline

JSON Formatter — validate and format your JSON before generating a schema.
JSON to TypeScript — generate TypeScript types alongside your JSON Schema.
API Response Mockup — generate mock data that conforms to your schema.

Frequently asked

Is my data sent to a server?: No. All schema generation and validation runs 100% in your browser. Your JSON data never leaves your device.
What is JSON Schema?: JSON Schema is a vocabulary for annotating and validating JSON documents. It defines the structure, data types, required fields, and constraints of a JSON object. It is used for API documentation (OpenAPI), form validation, configuration validation, and data contracts.
What is the difference between JSON Schema draft-07 and draft-2020-12?: Draft-2020-12 is the latest version with improved support for dynamic references, unevaluatedProperties, and prefixItems for tuple validation. Draft-07 is the most widely supported version — used by most validators, code generators, and OpenAPI 3.0. Use draft-07 for maximum compatibility.
Can I validate JSON against a schema?: Yes. Paste your JSON Schema in the schema panel and your JSON data in the data panel. The tool validates the data against the schema and shows all validation errors with JSON Pointer paths to the failing fields.
Can I generate a schema from a TypeScript interface?: Yes. The TypeScript tab converts TypeScript interface definitions to JSON Schema. This is useful for generating API documentation schemas from your existing TypeScript types.