JSON Schema Generator - Generate JSON Schema from JSON

JSON Input

Generated Schema

What Is a JSON Schema Generator?

JSON Schema describes the structure of JSON data: required fields, types, allowed values, formats. A schema generator infers a schema from sample JSON. You paste example data, and it produces a schema that describes that structure. You can then use the schema to validate other JSON or to document APIs.

This tool runs in your browser. Paste your JSON, and it generates a JSON Schema draft. Nothing is sent to a server.

How to Use This Tool

Paste Sample JSON

Paste JSON that represents the structure you want to describe. Use Sample or Upload if needed. The generator infers types from the values (string, number, boolean, array, object).

Review the Schema

The right panel shows the generated schema. It may include type, properties, required, and nested schemas for objects. You can edit it manually if needed.

Copy or Download

Use Copy or Download to get the schema. For validating JSON against a schema, use the JSON Validator or a library like Ajv.

JSON Schema Examples

Generate a schema from sample JSON. Telecom-themed example:

JSON input

Input

Generated schema

Output

When to Use a Generated Schema

Generated schemas are a starting point. They capture the structure of your sample data but may be too strict or too loose. You might need to add required arrays, adjust types, or add enum for allowed values. The JSON Schema docs explain the full vocabulary. For API documentation, tools like OpenAPI can reference JSON Schema.

Frequently Asked Questions

Can I validate JSON with this schema?

This tool only generates schemas. To validate, use the JSON Validator or a library like Ajv in your code.

What if my JSON has different shapes?

The generator infers from the sample you provide. If your JSON can have multiple shapes (e.g. optional fields), the schema might need manual edits. Use oneOf or anyOf for variants.

Is my data sent anywhere?

No. Generation runs in your browser.

Which JSON Schema draft is used?

The tool may use draft-07 or draft-2020-12. Check the generated schema for $schema to see which version. The JSON Schema spec has the details.

Can I use this for API responses?

Yes. Paste a typical API response. The generated schema describes that structure. You can then use it in OpenAPI/Swagger or for documentation.

Related Tools

Learn more at json-schema.org and JSON Schema learn. For validation in code, see Ajv. For JSON, see json.org and MDN. For API documentation, see OpenAPI.