Free JSON Schema Generator

How to Generate a JSON Schema

Paste your sample JSON into the left panel and the generated JSON Schema appears instantly on the right. The tool recursively infers types for every field, detects common string formats like dates and emails, and marks all fields as required by default. You can also upload a .json file. Copy the output or download it as a .schema.json file.

Understanding JSON Schema

JSON Schema provides a contract for what your JSON data should look like. It specifies which fields are expected, what types they should be, and whether they are required. Schemas are used for API request/response validation, form generation, documentation, and code generation. Draft-07 is the most commonly supported version, compatible with popular validators like Ajv, jsonschema (Python), and many others.

Frequently Asked Questions

What is JSON Schema?

JSON Schema is a vocabulary that lets you annotate and validate JSON documents. It describes the structure, types, and constraints of your data, making it useful for documentation, validation, and code generation.

Which JSON Schema draft does this tool use?

This tool generates schemas conforming to JSON Schema draft-07, which is the most widely supported draft across validators and tooling.

Does it detect string formats?

Yes — the generator automatically detects common formats including date-time, date, email, and URI. These are added as format annotations in the generated schema.

How are required fields determined?

For a single object, all fields are marked as required by default. When inferring from an array of objects, a field is only marked required if it appears in every object in the array.

Does it handle nested objects and arrays?

Yes — the schema generator recursively infers types for nested objects and arrays. For arrays with mixed types, it uses anyOf to represent the possible item schemas.

Is my data safe?

All schema generation happens locally in your browser using JavaScript. Your JSON is never uploaded to any server. It's safe to use with sensitive or proprietary data.