Web Tools
Mock Data Generator
Generate fake JSON data with configurable fields and seedable PRNG. Choose from 18 field types including names, emails, IPs, UUIDs, dates, booleans, colors, URLs, phone numbers, and more. Reproducible output with seed control. Runs entirely in your browser — your data never leaves your machine.
mock fake data generator json test seed fixture
Published May 29, 2026
All interactive tools run entirely in your browser. Your data never leaves your device.
How It Works
Define your data schema by adding fields with a name and type, set the row count and seed, and get reproducible fake JSON data instantly. The seedable PRNG ensures the same seed always produces the same output, perfect for deterministic test fixtures.
Features
- 18 field types: ID, first/last/full name, email, username, IPv4, UUID v4, date, boolean, integer, float, hex color, URL, phone, company, sentence, word
- Seedable PRNG: Mulberry32 algorithm — same seed = same output, every time
- Configurable row count: 1 to 1,000 rows
- Dynamic field editor: add, remove, rename, and reorder fields on the fly
- 5 presets: User List, Product Catalog, Server Log, Company Directory, Blog Posts
- Valid JSON output: pretty-printed, ready to copy and paste
- Copy to clipboard: one-click copy of the full JSON output
- Private: runs entirely in the browser — no data transmitted
Use Cases
- Generating test fixtures for unit and integration tests
- Populating development databases with realistic mock data
- Prototyping UI components that display lists or tables
- Creating sample API responses for frontend development
- Producing consistent, reproducible datasets for demos and documentation