What is JSON Schema used for?

JSON Schema is a standard vocabulary that allows you to annotate and validate JSON documents, ensuring incoming API requests and payloads adhere to expected structures and types.

How does this tool detect integer vs number types?

Numbers without decimal points (Number.isInteger) are typed as "integer", while numbers with fractional components are typed as "number".

How does it handle arrays of objects?

The generator inspects elements of an array and creates an "items" sub-schema defining the expected object properties for array items.

Can I use this generated schema in Ajv or FastAPI?

Yes! The generated schema complies with standard JSON Schema specs and works seamlessly with Ajv, Python jsonschema, FastAPI, and OpenAPI 3.0+.

Does this generator upload my JSON data anywhere?

No. All parsing and schema building takes place strictly inside your browser environment.

JSON Schema Generator

Instantly generate standard JSON Schema Draft-07 & 2020-12 definitions from any JSON data.

100% free
Private in browser
No signup
No watermarks

JSON Schema Generator

Convert sample JSON payloads into valid Draft-07 and 2020-12 JSON Schema definitions.

Sample JSON Input

Require All Properties

Generated JSON Schema

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "GeneratedSchema",
  "type": "object",
  "properties": {
    "userId": {
      "type": "integer"
    },
    "username": {
      "type": "string"
    },
    "email": {
      "type": "string"
    },
    "isVerified": {
      "type": "boolean"
    },
    "tags": {
      "type": "array",
      "items": {
        "type": "string"
      }
    },
    "metadata": {
      "type": "object",
      "properties": {
        "loginCount": {
          "type": "integer"
        },
        "lastLoginIp": {
          "type": "string"
        }
      },
      "required": [
        "loginCount",
        "lastLoginIp"
      ]
    }
  },
  "required": [
    "userId",
    "username",
    "email",
    "isVerified",
    "tags",
    "metadata"
  ]
}

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About JSON Schema Generator

Instantly generate standard JSON Schema Draft-07 & 2020-12 definitions from any JSON data. Use this free client-side tool on TheToolss with zero installation and complete privacy.

How to use JSON Schema Generator

Paste your sample JSON data or API payload into the editor.
Choose your preferred JSON Schema draft (Draft-07 or Draft 2020-12).
Toggle whether all top-level properties should be marked as required.
Copy the generated JSON Schema to validate incoming API requests.

Key features

Automatic recursive schema inference for deeply nested JSON objects and arrays
Precise type classification: distinguishes integers from floating point numbers
Support for Draft-07 and modern Draft 2020-12 JSON Schema specifications
Optional automatic required fields generation for strict API validation
100% private in-browser generation with zero server dependencies

Frequently asked questions

What is JSON Schema used for?: JSON Schema is a standard vocabulary that allows you to annotate and validate JSON documents, ensuring incoming API requests and payloads adhere to expected structures and types.
How does this tool detect integer vs number types?: Numbers without decimal points (Number.isInteger) are typed as "integer", while numbers with fractional components are typed as "number".
How does it handle arrays of objects?: The generator inspects elements of an array and creates an "items" sub-schema defining the expected object properties for array items.
Can I use this generated schema in Ajv or FastAPI?: Yes! The generated schema complies with standard JSON Schema specs and works seamlessly with Ajv, Python jsonschema, FastAPI, and OpenAPI 3.0+.
Does this generator upload my JSON data anywhere?: No. All parsing and schema building takes place strictly inside your browser environment.