Your data never leaves your browser
Realistic values — not "string_1"
1, 3, 5 or 10 instances at once
Ready for tests, Postman, Storybook
Always free
When do you need mock JSON from a schema?
Four common workflows.
API testing and fixtures
Generate realistic test fixtures from your OpenAPI or JSON Schema definitions. Use the mock data directly in unit tests, Postman collections or mock servers — without writing fixture data by hand.
Frontend development
When the backend API is not ready, generate mock responses from the agreed schema. Seed your frontend app, Storybook components or UI tests with realistic data that matches the final structure.
Schema validation testing
Generate a valid instance from your schema, then validate it against the schema with AJV to verify the schema itself is correct. A generated instance that fails validation reveals a bug in the schema.
Documentation examples
OpenAPI docs, Confluence pages and README files need JSON examples alongside schema definitions. Generate realistic examples directly from the schema to keep them always in sync with the structure.
Related tools
Popular searches
json schema to json converter
json schema to json
generate json from json schema
json schema to json object
json schema mock data generator
json schema to sample json
json schema to json online
mock json from schema
json schema to json example
json schema to json generator
Common questions about generating JSON from a JSON Schema.
How do I generate JSON from a JSON Schema?
Paste your JSON Schema into the input above and click Generate. The tool reads the type definitions and creates a valid JSON instance with realistic example values. Nested objects, arrays and required/optional fields are all handled automatically.
What is the difference between a schema and a JSON instance?
A JSON Schema is a blueprint — it describes what a JSON document should look like: which fields exist, their types and constraints. A JSON instance is actual data that conforms to that blueprint. This tool generates a valid instance from your schema blueprint.
Does the generator support Draft-07 and 2020-12?
Yes. The generator reads the $schema field and supports both versions. The core type keywords (type, properties, items, required) are identical between Draft-07 and 2020-12 — the generator handles both correctly.
Can I generate multiple mock instances at once?
Yes. Set Instances to 3, 5 or 10 and the output will be a JSON array with that many objects, each generated independently with slightly varied values — useful for seeding databases or populating frontend fixtures.
