Mock Data Generator

Create mock datasets in your browser — users, products, addresses, or a custom field checklist — then copy or download JSON or CSV. Optional seed for reproducible rows.

Users, products, addresses, or custom fields

JSON or CSV output up to 1,000 rows

Optional seed for reproducible datasets

Copy or download the result

Runs fully client-side — nothing uploaded

How to generate mock data

Choose a template

Use users (name, email, id), products, addresses, or build a custom schema with the field checklist.

Set count and format

Generate between 1 and 1,000 rows as JSON or CSV. Optionally enter a seed so the same settings always produce the same dataset.

Generate

Click Generate to build the dataset entirely in your browser.

Copy or download

Copy the output to the clipboard or download a .json / .csv file for fixtures and demos.

Why a browser mock data generator#

Teams need realistic placeholder rows for UI demos, API fixtures, Storybook stories, and load tests — without pasting production PII into a third-party form. A mock data generator online that runs locally keeps sample names and emails on your machine while still giving you structured JSON or CSV you can drop into tests.

This tool is a lightweight fake data generator online: no npm faker bundle, no account, and no upload. Templates cover the common shapes (users, products, addresses), and the custom checklist lets you mix fields when a fixed schema is not enough.

JSON vs CSV for fixtures#

Search demand for mock data generator json usually means Nest/Express fixtures, frontend mocks, or seeding scripts that JSON.parse a file. Pretty-printed JSON keeps nested objects readable and matches how most JavaScript tooling expects sample data.

Mock data generator csv fits spreadsheets, bulk imports, and data pipelines. Headers follow the selected field ids (id, fullName, email, …), and cells with commas or quotes are escaped so Excel and csv-parse stay happy.

Seeds and reproducibility#

Without a seed, each Generate pass draws fresh values (via the Web Crypto API). With a seed string or number, the same template, fields, and count always yield the same rows — useful when a PR review or CI assertion needs a stable fixture instead of a moving target.

Seeds are hashed into a small PRNG (mulberry32). They are for determinism in demos and tests, not for cryptography. Treat generated emails and names as clearly fake sample data.

Using the output in JavaScript#

People looking for a mock data generator javascript workflow typically want something they can paste into a .json file or import in Vitest/Jest. Download JSON, save it next to your tests, and import it as a module or read it with fs in Node.

For Playwright or Cypress, CSV or JSON fixtures avoid hard-coding dozens of objects in the spec. Regenerate with the same seed when the schema changes so reviewers can re-run and get an identical sample set.

Frequently asked questions

Is this mock data generator free and private?

Yes. It is a free mock data generator online that runs entirely in your browser. Rows are never uploaded to a server.

Can I export mock data as JSON and CSV?

Yes. Switch the format between JSON and CSV, then copy or download. JSON is pretty-printed; CSV includes a header row with the field names.

How do I get the same dataset every time?

Enter an optional seed (any string or number). With the same template, fields, count, and seed, Generate returns identical rows.

What does the custom field checklist do?

Custom mode lets you pick which columns to include — names, emails, addresses, prices, UUIDs, booleans, dates, and more — instead of using a fixed users/products/addresses template.

Is this a JavaScript faker library?

No npm package is required. Generation is implemented in plain client-side JavaScript inside the page so you can produce fixtures without adding faker to your project.

How many rows can I generate?

Between 1 and 1,000 rows per run. That covers most UI mocks and small seed files; generate again if you need another batch.

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