Free Online Tool
JSON to Schema Generator
Paste any JSON and generate a valid JSON Schema definition. Detects types, required fields, arrays, and nested objects.
Instant
No uploads
Type inference
What Is JSON Schema?
JSON Schema is a vocabulary that allows you to annotate and validate JSON documents. It describes the structure of JSON data — what properties exist, their types, which are required, and how nested objects and arrays are structured. JSON Schema is used for API validation, form generation, configuration validation, and data documentation.
Our tool reverses the process: instead of writing a schema by hand, you paste an example JSON document and the tool infers the schema automatically. This is especially useful when you have API responses or data samples but no formal schema definition yet.
Structured data helps search engines understand your content beyond just the text on the page. But writing JSON-LD by hand means memorizing schema.org types, properties, and nesting rules. This generator lets you pick a schema type, fill in the fields, and get valid JSON-LD output that you can paste directly into your HTML. It supports the most common types — Article, Product, FAQ, HowTo, and more.
Key Features
Instant Generation
Paste any JSON object or array and get a complete JSON Schema definition immediately. No processing delay — the schema is built client-side in your browser.
Privacy First
Your JSON data never leaves your browser. There are no API calls, no server uploads, and no logging. Process sensitive API responses safely.
Automatic Type Detection
Infers string, number, integer, boolean, null, object, and array types. Distinguishes between integers and floating-point numbers for precise schemas.
Required Fields Detection
Automatically marks non-null fields as required in the generated schema. This creates stricter validation rules that match your actual data structure.
Nested Object Support
Handles deeply nested objects and arrays of objects. Each level of nesting produces its own properties/items definition in the schema.
Draft-07 Output
Generates valid JSON Schema Draft-07 with proper $schema declaration, ready for use with Ajv, jsonschema, and other standard validation libraries.
Who Is This Tool For?
Backend Developers
Generate validation schemas from API response samples. Use the schema to validate incoming requests or document your API contract with OpenAPI/Swagger.
Frontend Developers
Create form validation schemas from your data models. JSON Schema integrates with libraries like react-hook-form, Formik, and Zod for type-safe validation.
DevOps & Platform Engineers
Validate configuration files (JSON configs, infrastructure templates) against generated schemas to catch errors before deployment.
API Designers
Quickly prototype API schemas from example payloads. Iterate on your data model by modifying the JSON sample and regenerating the schema instantly.
Type Inference Reference
| JSON Value | Schema Type | Notes |
|---|---|---|
| "hello" | string | Any quoted value |
| 42 | integer | Whole numbers |
| 3.14 | number | Decimal values |
| true / false | boolean | Boolean literals |
| null | null | Null values (not required) |
| [...] | array | Items type from first element |
| { ... } | object | Properties recursively inferred |
Frequently Asked Questions
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