JSON Schema Fixture Generator

Generate seeded, illustrative fixtures locally, with explicit subset validation and limitations.

JSON Schema

Seed Variants Intent Optional properties

Subset uses 2020-12-style keyword shapes. Supported constraints: local JSON Pointer $ref, boolean schemas, type, const, enum, numeric and size bounds, multipleOf, required/properties/additionalProperties, items/prefixItems/uniqueItems, allOf/anyOf/oneOf/not, and listed format presets. $ref siblings are conjunctive. Pattern and unknown keywords are reported but ignored. “Valid” means this supported subset only. Invalid mode first builds a valid fixture, then verifies a supported constraint fails.

Limits: 1 MiB schema, 5 MiB output, depth 40, 5,000 generation/schema nodes, 20,000 validation visits, 500 object properties, 1,000 array items, 10,000 generated string characters, and 25 variants. Local # references only; recursive references are reported and fail if no finite fixture is found.

Generated JSON

Validation and limitations

Generate fixtures to inspect supported-subset results.