Is the data really 'realistic' or just gibberish?

Real names and addresses pulled from regional census distributions — Smith and Garcia turn up more often than Zyxbyx for English names. Phone numbers follow regional dialing formats. Realistic enough for demos and unit tests; obviously fake enough for legal safety.

Will the data pass validation?

Generally yes — emails are RFC 5321-valid, phone numbers match regional formats, dates are in valid ranges. Specific test cases (must include a + character in email, edge dates) require explicit configuration.

Can I seed for reproducible output?

Yes — toggle deterministic mode and pick a seed. Same seed = same data, every time. Useful for snapshot tests and reproducible demo recordings.

users · contacts · products · transactions

Generate mock data for any purpose

Q: Is anything sent to a server?

No — all generation runs in your browser. Output stays local.

Four ready presets — users, contacts, products, transactions. Pick a row count up to 10,000 and download as JSON or CSV. Runs entirely in your browser.

Mock Data Generator

Rows

—

users

Output

0 B

empty

Preset

users

schema

Status

—

local

input · preset info

Users

id, username, name, email, age, joined

Contacts

name, email, phone, address, city, state, zip

Products

sku, name, category, price, stock

Transactions

id, type, amount, currency, status, timestamp

output · json (0)

Pick a preset, set a row count, then Generate

Quick Start

How to generate mock data

Skip schema bikeshedding — four presets cover the common shapes. Tweak the row count and download as JSON or CSV.

01
Pick a preset
Users, contacts, products, or transactions — each with sensible fields.
Inputs are treated as UTF-8 throughout the pipeline and validated client-side as you type — nothing dispatches until the value is well-formed.
presetinpututf-8client-sidevalidated
preset · textusers · set
```
id, username, name, …
```
loaded · parsedclient-side
02
Choose count
Up to 10,000 rows per generation.
Each toggle re-computes through a memoised hook, so flipping options never resets your input and the UI stays snappy on large inputs.
countoptionslivememoisedtoggles
rows · memoised10 · live
```
10 rows
```
options set · memoisedlive
03
Generate
Output is a JSON array with realistic fake values.
Randomness — where used — comes from crypto.getRandomValues, never Math.random. Heavy work sits in useMemo.
datacomputeinstantlocaldeterministic
out · instantjson · computed
```
[ { "id": 1, … } ]
```
computed · instantinstant
04
Copy or download
Grab as .json or .csv.
Copy writes through navigator.clipboard and downloads use a Blob — zero network traffic. Same input plus same options always yield the same bytes.
exportcopydownloadzero-networkreproducible
✓ · copiedready · copied
```
✓ mock-users.json
```
shipped · ready to shipsuccess

Pro tips

Pro tips for everyday utilities

Reach for crypto.getRandomValues

Cryptographically random for IDs, tokens, salts. Math.random is for animation and games, not security.

Sort IDs lexicographically

UUID v4 has no time ordering. Use ULID or UUID v7 if you need sorted IDs.

Mock data with seeds

Faker-style libraries can be seeded so tests are reproducible. Embed the seed in the fixture file.

Reference cards beat memory

Cheatsheets for Vim, Git, Docker, Linux signals are faster than man pages when you’re mid-flow.

Browser APIs vary

Touch events, gamepads, and clipboard differ across vendors. Feature-detect before use.

Persist in the right place

localStorage for user preferences, sessionStorage for transient state, IndexedDB for structured data.

Use Cases

When to generate mock data

Seed databases, design mockups, integration tests.

API tests

Stub realistic JSON without real users. Random values come from crypto.getRandomValues — cryptographically secure for tokens, salts, and session IDs. Math.random is deterministic enough for animations but predictable enough to be a security bug.

CSPRNG-backed

Design comps

Avoid 'Lorem ipsum' in product mockups. Pair with hashids, ULID, or UUID v7 when you need both random and sortable — useful for primary keys, public-facing IDs, and event log ordering without a sequence column.

reproducible

Demo seeds

Populate a fresh dev DB instantly. Output is deterministic given the same seed, so fixtures and tests stay reproducible across CI runs and contributor machines. Embed the seed in the fixture file for full replay.

snappy

Storybook fixtures

Realistic props for component states. Heavy work runs through useMemo so the UI stays snappy on large inputs. Same input + same options yields identical bytes — the kind of stability snapshot tests rely on.

feature-detected

Load tests

10K row dump for upload stress tests. Storage tools persist to the right backend: localStorage for user preferences, sessionStorage for transient state, IndexedDB for structured data. Pick the right shelf and quota worries disappear.

deterministic

Sales demos

Show a populated app to prospects safely. Browser feature detection: clipboard, fullscreen, gamepad, and Web Bluetooth APIs gracefully fall back when unavailable. No surprise white screens on Safari or older Firefox.

production-ready

FAQ

Frequently asked questions

Are the names real?

No — first and last names come from a curated pool. No actual person is referenced.

Can I customize the schema?

These four presets cover common shapes. For arbitrary schemas, use Mock JSON from Schema or Mock CSV Rows.

Are emails real domains?

They use example.com and similar safe domains so test mail never reaches anyone.

What's the row cap?

10,000 per generate. Bigger fixtures? Generate multiple batches.

Is anything sent to a server?

No — generation runs locally in your browser.

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Something missing?

Tell us what you need. We ship the top requests every two weeks.

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