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JSON Schema Generator

Generate JSON Schema from JSON data automatically

⚙️Schema Options

Schema Draft Version

Include "required" arrays

Include "description" placeholders

Include "additionalProperties: false"

💻Input JSON

💻JSON Schema Output

// JSON Schema output will appear here...

Free Online JSON Schema Generator

Our JSON Schema generator analyzes sample JSON data and instantly produces a valid JSON Schema definition with accurate type detection, nested object handling, and array item inference. Simply paste a JSON object, choose your preferred draft version, and get a schema you can use for API validation, form generation, or documentation -- all without writing a single line of schema code by hand.

The tool supports JSON Schema draft-04, draft-06, and draft-07, covering the most widely adopted versions in the ecosystem. It recursively walks through your JSON structure, detecting strings, numbers, integers, booleans, nulls, objects, and arrays. For arrays, the schema is inferred from the first element, ensuring accurate item definitions even for complex nested structures.

Configurable options let you toggle required property arrays, add description placeholders for documentation, and enforce additionalProperties: false for strict validation. When you are satisfied, download the result as a .schema.json file or copy it to your clipboard with one click. Everything runs locally in your browser -- your data is never uploaded to a server.

Key Features

Support for JSON Schema draft-04, draft-06, and draft-07 with proper $schema URI
Automatic type detection for string, number, integer, boolean, null, object, and array
Recursive schema generation for deeply nested objects and arrays
Array item type inference based on the first element
Configurable "required" property arrays to control validation strictness
Optional "description" placeholder generation for self-documenting schemas
Toggle for "additionalProperties: false" to enforce strict object shapes
Download the generated schema as a .schema.json file
One-click copy to clipboard
Preloaded sample JSON for quick experimentation

How to Use the JSON Schema Generator

Configure schema options: Select the draft version, and toggle required arrays, descriptions, and additionalProperties according to your needs.
Paste your JSON: Enter or paste a sample JSON object into the input panel. You can also click "Sample JSON" to load an example.
Generate the schema: Click "Generate Schema" to produce the JSON Schema output in the right panel.
Review and refine: Inspect the output. Adjust options like required fields or descriptions and regenerate as needed.
Export the schema: Click "Copy" to place the schema on your clipboard, or "Download .schema.json" to save it as a file.

Use Cases

OpenAPI / Swagger specifications: Generate schema definitions for request and response bodies in your API documentation.
Backend request validation: Create schemas to validate incoming JSON payloads in Express, FastAPI, Spring Boot, or other frameworks.
Frontend form generation: Feed schemas into libraries like react-jsonschema-form to auto-generate UI forms from data models.
Data contracts: Define and share structured data contracts between microservices or between frontend and backend teams.
Configuration validation: Validate JSON config files in CI/CD pipelines to catch structural errors before deployment.
Database migration planning: Document expected data shapes when designing new tables or collections.
IDE auto-completion: Reference a JSON Schema in VS Code settings to enable IntelliSense and validation for custom JSON files.

Frequently Asked Questions

Is this tool free?

Yes, the JSON Schema generator is completely free with no sign-up or usage limits. Generate schemas for any number of JSON objects at no cost.

Is my data secure?

Yes. All schema generation happens in your browser. Your JSON data is never sent to any server, making it safe to use with proprietary API payloads or internal data structures.

What is JSON Schema?

JSON Schema is a declarative vocabulary for annotating and validating JSON documents. It describes the expected structure, data types, required properties, and constraints of a JSON object. It is widely used in API specifications (OpenAPI/Swagger), form generation libraries, and configuration validation tools.

Which draft version should I use?

Draft-07 is recommended for most projects as it is the most widely supported version across validation libraries and tooling. Use draft-04 or draft-06 only if your toolchain specifically requires an older version.

Can I edit the generated schema?

The generated schema is a starting point. After downloading or copying it, you can manually add constraints like minLength, maximum, enum values, or pattern regex that cannot be inferred from sample data alone.

Does it handle mixed-type arrays?

The generator infers array item types from the first element. If your array contains mixed types, you may need to manually adjust the items definition to a oneOf or anyOf schema after generation.

Tips & Best Practices

Provide representative sample data: Include all possible fields in your sample JSON so the schema captures the full structure.
Enable required arrays: Turn on the "required" option to enforce mandatory fields when using the schema for validation.
Add descriptions later: Enable description placeholders during generation, then replace them with meaningful documentation before sharing the schema.
Use additionalProperties: false for strict APIs: This prevents clients from sending unexpected fields that could cause issues downstream.
Validate after generation: Test your schema against multiple sample payloads using a JSON Schema validator to ensure it covers edge cases.
Version your schemas: Store schema files in version control alongside your API code to track changes over time.