Mock Data Generator
Generate realistic sample data in JSON, CSV, or SQL for testing and prototyping. Runs locally in your browser.
Awaiting generation
Saved templates & presets
Reuse and share schema + options with one click.
Template gallery
Save current
Output
Your generated data will appear here.
How to use
- Pick a schema or preset, then choose JSON, CSV, SQL, or schema exports.
- Set record count, seed, and locale, then click Generate.
- Copy the output, download it, or export GitHub-ready examples.
Notes & privacy
All data is generated locally in your browser; nothing is uploaded.
For larger datasets or custom schemas, generate in smaller batches or adjust the code client-side.
What is a mock data generator?
A mock data generator creates realistic sample data for tests, demos, QA, and prototyping. Instead of hand-editing JSON or CSV files, you define a schema and generate consistent datasets on demand.
This tool runs fully in your browser with seeded output for deterministic snapshots. You can export JSON, CSV, SQL, JSON Schema, TypeScript, or OpenAPI examples and keep everything private with zero uploads.
Key features for test data and API mocks
Schema builder
Define fields, types, constraints, and enums with a live schema preview.
Seeded output
Use a seed to generate stable fixtures for regression tests and snapshots.
Relational presets
Generate linked collections with mapping templates and foreign keys.
Multi-format exports
Export JSON, CSV, SQL, JSON Schema, TypeScript, OpenAPI, Prisma, and MongoDB outputs.
Performance mode
Chunked generation handles large datasets with optional zip download.
Privacy-first
Everything runs client-side. No uploads, storage, or tracking by default.
Common mock data use cases
API development and QA
Generate predictable API responses for integration tests, Swagger examples, or mock servers.
UI demos and product previews
Populate dashboards with realistic user, transaction, and order data for prototypes and demos.
Database seeding
Export SQL, Prisma, or MongoDB insertMany scripts to seed local environments quickly.
Test fixtures
Copy Jest fixtures or Playwright mocks to keep automated tests consistent and maintainable.
Trust, Visibility & Ecosystem
Trust
- Client-side generation with no uploads.
- Seeded output for reproducible snapshots.
- Clear privacy notes and local processing.
Visibility
- Export GitHub-ready examples for docs.
- Structured data for richer search results.
- Metadata tuned for developer discovery.
Ecosystem
- Copy as Jest fixture or Playwright mock.
- Embed snippets for README and docs.
- API and CLI hooks for automation.
Frequently asked questions
Is this mock data generator free and private?+
Yes. The UI runs locally in your browser with no uploads. The API is optional for automation.
Can I generate deterministic fixtures?+
Yes. Add a seed to ensure the same schema and options always produce the same output.
Which formats are supported?+
JSON, CSV, SQL, JSON Schema, TypeScript, OpenAPI, Prisma, and MongoDB insertMany.
How do I create Jest fixtures or Playwright mocks?+
Generate data, then use the Copy Jest fixture or Copy Playwright mock buttons in the output panel.
Can I share a GitHub-ready example?+
Yes. Use Export GitHub example to download a Markdown snippet you can paste into a README.
Is the output safe for sensitive data?+
The generator creates synthetic data only. No real user data is processed or stored.