How to use the JSON Mock Data Generator
Generate mock JSON data:
1
Define your schema
Use the visual builder to add properties, selecting from 18 types including primitives, complex arrays, or nested objects.
2
Configure hierarchy
Group data logically by adding child fields under array or object nodes to perfectly match your target API response.
3
Set the record limit
Input exactly how many top-level objects you need, generating anywhere from 1 to 1,000 items in a single click.
4
Copy or download
Click generate to instantly get a valid JSON array, then use the one-click copy button or download the `.json` file.
When to use this tool
Use this when you need sample data for development or testing:
- →Writing Next.js frontend components while the backend API is still under development
- →Generating 500+ records of realistic dummy user profiles for database seeding in Prisma or TypeORM
- →Creating mock JSON payloads to test frontend virtualization and infinite scrolling performance
- →Drafting sample JSON responses to share in Swagger or OpenAPI documentation
- →Testing complex UI states like long addresses or extreme price formats without writing manual objects
Frequently asked questions
Q:What data types can I add to the mock schema?
You can map properties to 18 types powered by @faker-js/faker, including UUIDs, standard primitives (integers, floats, booleans), structural nodes (objects, arrays), personal data (names, emails), and generic text.
Q:Can I nest objects or arrays inside one another?
Yes. By selecting 'Object' or 'Array' as your field type, you can use the 'Add child' button to recursively define deeply nested JSON structures representing complex relational data.
Q:How do I use the generated JSON?
The tool outputs a standard JSON array string. You can download the `.json` file to use as a test fixture in Jest/Vitest, or copy the payload directly into a mocked fetch response or API route.
Q:Is my schema and generated data sent to a server?
Completely private. The schema building and faker.js data generation run entirely within your browser natively. No generated data is logged or transmitted externally.
Q:Is there a limit on how many JSON objects I can generate?
To maintain browser performance, you can generate up to 1,000 root-level objects per click. For larger datasets, you can generate and download multiple batches.