JSON to JSON Schema Generator Online Free — Create Schema from JSON | DevToolBox

Generate JSON Schema from JSON data online free. Auto-detect types, required fields, nested objects & arrays. Supports Draft 2020-12. Paste JSON, get schema instantly.

Title:

JSON Input

JSON Schema

About JSON to JSON Schema Conversion

JSON Schema is a vocabulary for annotating and validating JSON documents. It's widely used for API documentation (OpenAPI/Swagger), form generation, configuration validation, and data interchange. This tool analyzes your JSON data and generates a JSON Schema (draft-07) that describes its structure. It correctly identifies types, marks all existing fields as required, handles arrays with item schemas, and creates nested schemas for objects. The output can be used with any JSON Schema validator or integrated into OpenAPI specifications. All processing happens in your browser.

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How to Use

Paste your JSON data into the input panel
Set the schema title and description (optional)
Click Convert to generate the JSON Schema
Copy the schema for use with validators, OpenAPI, or Ajv

Common Use Cases

Creating JSON Schema for OpenAPI/Swagger documentation
Generating validation schemas for REST APIs
Building configuration file validators
Documenting data structures for team collaboration
Generating Ajv validators for Node.js applications
Creating form validation rules from sample data

Frequently Asked Questions

What JSON Schema draft is used?

The tool generates schemas following JSON Schema draft-07, which is widely supported by validators and tools.

Are all fields marked as required?

Yes. Since the tool infers the schema from sample data, all present fields are marked as required. You can adjust this manually after generation.

Does it handle nested objects?

Yes. Nested objects generate nested schema definitions with their own properties and required arrays.

Can I use this with OpenAPI/Swagger?

Yes. The generated JSON Schema is compatible with OpenAPI specifications. You can paste the schema into your API documentation.

How do I create JSON Schema from JSON?

Paste your sample JSON data into the input panel and click Convert. The tool automatically detects types (string, number, boolean, array, object), marks all fields as required, and generates a complete JSON Schema definition.

What is JSON Schema used for?

JSON Schema defines the structure and validation rules for JSON data. It's used for API request/response validation, form generation, configuration file validation, and data documentation in OpenAPI/Swagger specs.

Does it support arrays of objects?

Yes. Arrays containing objects generate an 'items' schema with the object's properties defined. Mixed-type arrays use 'anyOf' to describe all possible item types.