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JSON Schema Generator

LOCAL · Browser-Only

Generate JSON Schema from sample JSON data automatically

Input JSON

Generated Schema

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What is JSON Schema Generator?

Free online JSON schema generator to paste any JSON data and instantly generate a valid JSON Schema (draft-07) that describes its structure.

Generate a JSON Schema from a sample API response, build a request validation contract, or turn a config file into a schema. The tool automatically detects types (string, number, integer, boolean, null, array, object), generates properties for objects, infers array item types, handles deeply nested structures, and marks all top-level properties as required. Use the generated schema for API validation, form generation, OpenAPI work, documentation, or data contract enforcement. All processing runs locally in your browser - your data stays private. No signup required.

How to Use JSON Schema Generator

1Paste your sample JSON data into the input field on the left
2Click 'Generate Schema' or paste JSON to auto-generate the schema
3Review the generated JSON Schema on the right
4Click 'Copy' to copy the schema to your clipboard or 'Share' to create a shareable link

Frequently Asked Questions

What is JSON Schema?

JSON Schema is a vocabulary that allows you to annotate and validate JSON documents. It describes the structure, types, and constraints of your JSON data, and is widely used for API validation, form generation, and data documentation.

Which JSON Schema draft does this tool use?

This tool generates schemas conforming to JSON Schema draft-07 (http://json-schema.org/draft-07/schema#), which is the most widely supported and commonly used version.

How are arrays handled in the generated schema?

The tool inspects the first element of each array to infer the item type. If the first element is an object, it generates a full object schema for items. Empty arrays default to string items.

Is my JSON data safe?

Yes. All processing happens entirely in your browser using JavaScript. Your JSON data is never sent to any server, making this tool completely safe for sensitive or proprietary data.

How do I generate a schema from an API response?

Copy a representative JSON response from your API and paste it in. The tool walks the structure and produces a draft-07 schema with the right type for each field. Use that schema to validate future responses or to document the contract for consumers of your endpoint.

Can I use the generated schema for request validation?

Yes. The output is a standard JSON Schema, so you can feed it to any validator such as Ajv or a server-side library to validate incoming request bodies. Review the required array, since the generator marks top-level properties as required and you may want to relax optional fields.

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Keep reading: SQL Cheat Sheet and http status codes reference. Doing this in code instead? See the JSON and data endpoints.

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