JSON Schema Generator

The JSON Schema Generator is a free browser-based tool that automatically creates a JSON Schema definition from any sample JSON data. Instead of manually writing schema definitions for API validation, configuration files, or data contracts, you can paste a representative JSON example and get a complete, standards-compliant schema in milliseconds.

JSON Schema is a powerful vocabulary for annotating and validating JSON documents. It is widely used in API development to define request and response contracts, in configuration management to enforce valid settings, and in form generation to automatically build user interfaces from data models. By generating a schema from existing data, you can bootstrap your validation logic without starting from scratch.

The generator performs recursive type inference across your entire JSON structure. Primitive values are mapped to their corresponding JSON Schema types — string, number, integer, boolean, and null. Nested objects produce nested schema definitions with their own properties and optional required arrays. Arrays are analyzed to determine a consistent element type; if the array contains mixed types, a oneOf composition is generated automatically. Empty arrays produce an open items schema so you can refine them later.

All processing happens entirely in your browser using native JavaScript APIs. Your data never leaves your machine — there are no server round-trips, no logging, and no third-party analytics on your input. This makes it safe for sensitive payloads such as internal API responses, authentication tokens, and configuration files containing secrets. You can choose between Draft-07 and Draft 2020-12 schema versions, toggle required fields, add empty description placeholders for documentation, and control whether additional properties are allowed.

1. Paste or type your sample JSON into the Sample JSON panel on the left.
2. The generated JSON Schema appears automatically in the right panel as you type.
3. Select the Schema Version (Draft-07 or Draft 2020-12) to set the $schema URL.
4. Toggle All required to include or exclude required arrays for each object level.
5. Enable Add descriptions to insert empty description fields you can fill in later.
6. Toggle Additional properties to control whether objects accept properties not defined in the schema.
7. Click Copy or press Ctrl+Shift+C to copy the generated schema to your clipboard.