How JSON Schema Generation Works

A JSON Schema describes the structure and validation rules for a JSON object. It defines types, required fields, allowed values, nested objects, arrays, and more. On jsonmaster.com, you can instantly generate a JSON Schema from any JSON input.

Just paste your JSON data, and our tool automatically analyzes keys, values, arrays, and nested objects to create a complete and standards-compliant draft-07 JSON Schema.

Example Input JSON

{
  "string": "This is a string value",
  "number": 42,
  "boolean": true,
  "nullValue": null,
  "array": ["apple", "banana", "cherry"],
  "object": {
    "nestedString": "Nested string value",
    "nestedNumber": 123,
    "nestedBoolean": false
  },
  "emptyArray": [],
  "emptyObject": {},
  "unicodeString": "Unicode characters: αβγ",
  "escapeCharacters": "Escaped character",
  "url": "https://www.example.com",
  "date": "2024 03 31",
  "nestedArray": [
    [1, 2, 3],
    [true, false, null]
  ]
}

  

Generated JSON Schema Output

{
  "type": "object",
  "properties": {
    "string": { "type": "string" },
    "number": { "type": "number" },
    "boolean": { "type": "boolean" },
    "nullValue": { "type": "null" },
    "array": {
      "type": "array",
      "items": { "type": "string" }
    },
    "object": {
      "type": "object",
      "properties": {
        "nestedString": { "type": "string" },
        "nestedNumber": { "type": "number" },
        "nestedBoolean": { "type": "boolean" }
      }
    },
    "emptyArray": {
      "type": "array",
      "items": {}
    },
    "emptyObject": {
      "type": "object",
      "properties": {}
    },
    "unicodeString": { "type": "string" },
    "escapeCharacters": { "type": "string" },
    "url": { "type": "string", "format": "uri" },
    "date": { "type": "string" },
    "nestedArray": {
      "type": "array",
      "items": {
        "type": "array",
        "items": {}
      }
    }
  }
}

  

How to Generate JSON Schema on jsonmaster.com

• Step 1: Paste your JSON into the input editor.
• Step 2: Click Generate Schema.
• Step 3: The tool inspects value types, arrays, and nested objects.
• Step 4: A complete, formatted JSON Schema appears on the right.
• Step 5: You can copy the schema or use it in validation tools, API design, or documentation.

The generated schema follows the official JSON Schema Draft-07 specification, making it compatible with validators, API frameworks, OpenAPI, and backend systems.