How to Generate a JSON Schema from Sample JSON

What schema inference can determine

A generator can observe object properties, arrays and primitive value types in the supplied example. It can create a fast starting point for documentation and validation.

What one sample cannot prove

One example cannot reliably determine whether a field is optional, which string format is intended, the full range of allowed values or whether an array may contain other shapes.

• Review required fields.
• Add minimum and maximum constraints.
• Add enums only when the domain guarantees them.
• Describe nullable and optional behavior explicitly.

Generate, review and validate

Generate the draft schema, edit it to reflect the actual contract, then validate several valid and invalid examples. Include edge cases rather than relying only on the original sample.