AI JSON Schema Generator

We support Draft 2020-12 (the latest standard), Draft 7 (widely supported by validation libraries), and Draft 4 (for legacy systems). Each draft has slightly different syntax and features — for example, Draft 2020-12 uses prefixItems instead of items for tuple validation. The generator produces valid schemas for your chosen draft version.

Yes, paste a sample JSON object and the AI will infer the schema from the data types and structure. It goes beyond simple type inference — it recognizes patterns like email addresses, URLs, dates, and UUIDs and applies the appropriate format validators. It also infers which fields should be required based on whether they appear consistently in your sample.

The generator adds constraints appropriate to each field type: minLength and maxLength for strings, minimum and maximum for numbers, pattern for strings matching specific formats, enum for fields with fixed values, and format for standard types like email, uri, date-time, and uuid. These constraints catch invalid data before it reaches your application logic.

The generated schema can be used directly with JSON Schema validation libraries in any language — ajv for JavaScript, jsonschema for Python, or built-in validation in frameworks like FastAPI and NestJS. Simply save the schema to a file and reference it in your validation middleware to automatically reject requests with invalid data structures.

Strict mode sets additionalProperties to false, rejecting any properties not defined in the schema — ideal for APIs where you want tight control. Moderate mode allows additional properties but documents expected ones clearly. Flexible mode allows any additional properties, useful for extensible data formats where consumers may add custom fields.