JSON Schema Generator

Generate Draft-07 or 2020-12 JSON Schemas from sample JSON for function calling, structured outputs and validation. Also available as a REST API.

JSON example500 chars / 30 lines

Generated JSON Schema1,479 chars / 85 lines

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "properties": {
    "id": {
      "type": "integer"},
    "name": {
      "type": "string"},
    "version": {
      "type": "string"},
    "active": {
      "type": "boolean"},
    "rating": {
      "type": "number"},
    "tags": {
      "type": "array",
      "items": {
        "type": "string"}
    },
    "metadata": {
      "type": "object",
      "properties": {
        "created": {
          "type": "string"},
        "author": {
          "type": "string"},
        "downloads": {
          "type": "integer"}
      },
      "required": [
        "created",
        "author",
        "downloads"],
      "additionalProperties": false
    },
    "features": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "name": {
            "type": "string"},
          "category": {
            "type": "string"},
          "premium": {
            "type": "boolean"}
        },
        "required": [
          "name",
          "category",
          "premium"],
        "additionalProperties": false
      }
    },
    "config": {
      "type": "null"}
  },
  "required": [
    "id",
    "name",
    "version",
    "active",
    "rating",
    "tags",
    "metadata",
    "features",
    "config"],
  "additionalProperties": false
}

Valid JSON Schema (Draft-07)9 properties

How it works

Type detection

Detects string, number, integer, boolean, null, array, and object types automatically.

Nested objects

Recursively generates schemas for deeply nested objects and arrays of objects.

Mixed arrays

Handles arrays with mixed types using anyOf. Detects homogeneous arrays for cleaner schemas.

Edge cases

Handles empty arrays, null values, and distinguishes between integer and floating-point numbers.

Updated October 2, 2026. Provided as is. Check the output before you rely on it in production.

How to use JSON Schema Generator

1

Provide example JSON

Paste a representative JSON object that includes every property you want the schema to allow.
2

Pick the schema draft

Choose the JSON Schema draft your validator or AI API expects.
3

Review the generated schema

Check that every property is present, types are correct and array items are typed. Nested objects get their own schemas.
4

Add constraints by hand

Edit the copied schema to add minLength, pattern, enum, minimum, maximum and descriptions for documentation.
5

Validate real data

Use the schema with a validator such as Ajv, and test both valid and invalid examples.

Questions and answers

What is JSON Schema Generator?

JSON Schema is a JSON vocabulary that describes the structure and types a document must have; LLM APIs use it to define tool inputs and structured outputs. This tool infers a Draft-07 or 2020-12 schema from a sample, with options for titles, descriptions, examples, required keys and additionalProperties.

Does JSON Schema Generator store or send my data?

No. All processing happens entirely in your browser. Your JSON data never leaves your device — nothing is sent to any server.

Can I use the generated schema for AI function calling?

Yes. The generated schemas are compatible with OpenAI function calling, Anthropic tool use, and other AI APIs that require JSON Schema definitions for structured output.

REST API

Base URL

https://aidevhub.io/api/schema-generator/

No authentication, fair use. Abusive traffic is throttled at the edge; responses carry no quota headers. CORS enabled. OpenAPI spec

Endpoints

POST /api/schema-generator/ Generate JSON Schema from example data

Example

curl -X POST https://aidevhub.io/api/schema-generator/ -H "Content-Type: application/json" -d '{"example": "{\"name\": \"Alice\", \"age\": 30}"}'

const res = await fetch("https://aidevhub.io/api/schema-generator/", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
  "example": "{\"name\": \"Alice\", \"age\": 30}"
}),
});
const data = await res.json();
console.log(data);

import requests

res = requests.post(
    "https://aidevhub.io/api/schema-generator/",
    json={"example":"{\"name\": \"Alice\", \"age\": 30}"},
)
print(res.json())

Example Response

{
  "schema": {
    "type": "object",
    "properties": {
      "name": {
        "type": "string"
      },
      "age": {
        "type": "integer"
      }
    },
    "required": [
      "name",
      "age"
    ]
  }
}

For AI agents: how to call this tool

Machine-readable contract, endpoints and examples. Humans can ignore this section.

Best Path For Builders

Dedicated API endpoint

Deterministic outputs, machine-safe contracts, and production-ready examples.

Dedicated API

https://aidevhub.io/api/json-schema-generator/

OpenAPI: https://aidevhub.io/api/openapi.yaml

GET /api/json-schema-generator/ GET json-schema-generator

POST /api/json-schema-generator/ POST json-schema-generator

JSON Schema Generator