Mock Data Generator
Define a schema, generate realistic test data, and export it as JSON, CSV, SQL, XML or YAML. Runs 100% in your browser — nothing is uploaded.
Schema Builder
Define your fields, generate realistic records, export in any format
1 – 1,000 records per generation
Same seed + same schema = identical data. Perfect for reproducible test fixtures and demos.
Preview
Your generated data will appear here. Pick a template, then press Generate.Examples
Real output from the User template (10 records, locale en, no seed) in every export format.
[
{
"id": 1,
"name": "Emily Carter",
"email": "[email protected]",
"username": "emily_c42",
"phone": "+1 415-555-0142",
"birthday": "1993-06-18"
},
{
"id": 2,
"name": "Daniel Fischer",
"email": "[email protected]",
"username": "danny_f87",
"phone": "+1 617-555-0198",
"birthday": "1988-11-02"
}
]
id,name,email,username,phone,birthday 1,Emily Carter,[email protected],emily_c42,+1 415-555-0142,1993-06-18 2,Daniel Fischer,[email protected],danny_f87,+1 617-555-0198,1988-11-02
INSERT INTO users (id, name, email, username, phone, birthday) VALUES (1, 'Emily Carter', '[email protected]', 'emily_c42', '+1 415-555-0142', '1993-06-18'), (2, 'Daniel Fischer', '[email protected]', 'danny_f87', '+1 617-555-0198', '1988-11-02');
Field type reference
Every type, its output format and generation rule. All values are plausible but fictional.
| Type | Example output |
|---|
Emails use reserved example domains so they can never deliver to a real inbox.
Validation & edge cases
What this tool guarantees — and what to watch out for when feeding the output into tests.
Reproducibility
With a seed set, the same schema and settings always produce byte-identical output. Without a seed, each generation uses fresh cryptographic randomness.
Emails are safe by design
Addresses use @example.com and similar reserved domains (RFC 2606). They pass format validation but can never receive mail.
UUIDs are RFC 4122 v4
Generated with the browser Web Crypto API — the same 122-bit random space as server-side v4 UUIDs.
Names are fictional
First/last names are drawn from per-locale pools. Combinations are random; resemblance to real people is coincidence.
Volume limits
Up to 1,000 records per run, generated locally in milliseconds. For larger datasets, run several exports and concatenate.
Everything stays in your browser
The generator, name pools and formatters are plain JavaScript running locally. No schema, no seed and no output ever leave this page.
Common use cases
How developers use mock data day to day.
Frontend prototyping
Feed the JSON export straight into your fetch mock or component story to design against realistic payloads.
Database seeding
Export SQL INSERTs with your own table name, or CSV for LOAD DATA / spreadsheet imports.
API & QA testing
Pin a seed so every test run replays the exact same dataset — failures become reproducible.
Demos & screenshots
Fill empty states, tables and charts with plausible data that reads well in screenshots and stakeholder demos.