Internet Toolset

Comprehensive Tools for Webmasters, Developers & Site Optimization

JSON Schema Faker

JSON Schema Faker

This tool transforms your JSON Schema definitions into ready‑to‑use sample data in seconds, eliminating manual JSON authoring. By interpreting types, formats, constraints, and enumerations, it generates realistic payloads that strictly adhere to your specifications—perfect for mocks, UI prototypes, test fixtures, and documentation.

It handles nested objects and arrays, respects numeric and string boundaries, merges allOf subschemas, and randomly selects alternatives from oneOf/anyOf. Optional properties can be toggled on or off, and a seed ensures reproducible results. Finally, choose JSON or YAML output to fit any workflow.

  • Batch generation: produce 1–10 samples in one request to quickly build multiple fixtures.
  • Optional properties: include or omit non‑required fields for simpler or fuller examples.
  • Constraint compliance: obey minLength, maxLength, minimum, maximum, pattern, minItems, and maxItems.
  • Defaults & examples: honor your schema’s default values and examples arrays when present.
  • Unique arrays: enforce uniqueItems: true to avoid duplicates.
  • allOf merging: combine multiple subschemas into one comprehensive definition.
  • Reproducible output: specify a numeric seed for consistent sample sets across runs.
  • Flexible formats: get results in JSON or YAML to integrate with any toolchain.
Core Example

Schema:

{ "allOf": [ { "type":"object", "properties":{ "id":{ "type":"integer", "default":0 } }}, { "type":"object", "properties":{ "status":{ "type":"string","enum":["new","ready","done"] } }} ], "properties": { "email": { "type":"string","format":"email","examples":["a@x.com"] }, "tags": { "type":"array","items":{"type":"string"},"minItems":2,"uniqueItems":true } }, "required":["id","status","email"] }

Options: count: 2 | include_optional: ✖ | respect_constraints: ✔ | use_examples: ✔ | use_defaults: ✔ | unique_items: ✔ | seed: 42 | output: YAML

Output (YAML):

- id: 0 status: done email: a@x.com tags: - ihhexdvxrc - nbacghqta - id: 0 status: done email: a@x.com tags: - wrnhosizay - wnkieg - dcmdllt - zbxordm
Use Cases
  • Auto‑create realistic fixtures for front‑end development without backend services.
  • Integrate into test suites for unit, integration, and contract testing.
  • Populate API documentation and code samples with credible data.
  • Validate schema changes by comparing generated output against expected shapes.
  • Generate inputs for load‑testing or benchmark scripts that reflect real‑world variations.