Stop Doing This Wrong: Fake User Data Generator for Development
Oct 23, 2026 · AI-assisted
You need a hundred users with believable names, emails, signup dates, and addresses — right now, before you can test the onboarding flow. So you either paste a schema into some SaaS mock-data site and hope nothing sensitive is in there, or you spin up a quick faker.js script in a terminal. Both work. They fail in different ways.
This is a comparison of the two paths I actually reach for: a browser-based generator running faker.js locally, and the CLI/script route. The keyword is "fake user data generator for development" because that's the job — not marketing fluff, just realistic rows you can drop into a fixture file or a seed script.
Quick comparison
Here's the honest split, based on what each approach is good at.
| Browser tool (Mock Data Generator) | CLI / faker.js script | |
|---|---|---|
| Setup time | Open a tab, build a schema | Install Node, write a script, run it |
| Data leaves your device | No — faker.js runs in the browser | No |
| Schema editing | Point-and-click fields, pick types | Edit code, re-run |
| Row limits | Up to 20,000 rows free; unlimited on Pro | Whatever your machine handles |
| Field types | 15 free; 30+ incl. locale data on Pro | Whatever you code |
| Export | JSON or CSV; SQL INSERT + ZIP on Pro | Whatever you write |
| Repeatability | Save schemas in IndexedDB (Pro, 20 schemas) | Commit the script to the repo |
The browser tool is a schema builder wrapped around faker.js. You add fields, choose types (name, email, address, date, and so on), set a row count, generate, then preview and download as JSON or CSV. Nothing is uploaded — the faker.js library runs locally in the page. That last part matters more than people admit when the "fake" data is modeled on a real customer list.
When the browser tool wins
A few situations where I'd pick the tab over the terminal every time:
You're not the one who'll maintain the script. If a QA person or a designer needs 500 test users for a staging environment, handing them a saved schema beats handing them a Node script they have to debug. They open the tool, pick the schema, hit generate, download the file.
You're prototyping the shape of the data. Building a schema visually is faster than iterating on a faker.js script when you're still deciding which fields exist. Add firstName, realize you also want lastName and fullName, adjust — no re-running, no console errors.
You need SQL INSERT output. If you're seeding a Postgres or MySQL table, the Pro export gives you INSERT statements directly. Writing that by hand in a script is tedious and easy to get wrong on quoting and escaping.
Privacy is a hard requirement. A SaaS mock-data generator that accepts a schema over the network is fine for firstName and email. It's less fine when your schema encodes internal field names, enum values, or ID formats. A local generator sidesteps the question entirely. The privacy page spells out the browser-only model if you need to justify it to someone.
You want multiple formats at once. Pro's ZIP export bundles multiple output formats in one download, which is handy when the frontend wants JSON and the DBA wants SQL from the same dataset.
How to use the Mock Data Generator
- Build a schema. Add fields and pick types — name, email, address, date, and more. Start with the fields your user table actually has.
- Generate. Choose a row count between 1 and 20,000 (free tier) and generate realistic fake data.
- Export. Preview the rows, then download as JSON or CSV. Pro adds SQL INSERT and ZIP export.
That's the whole loop. No account, no upload, no waiting on a queue.
When to use alternatives
I'm not going to pretend the browser tool replaces a script in every case, because it doesn't.
You need relational data. A script can generate 50 users, then 200 orders where each user_id points at a real generated user. A flat schema builder produces independent rows. If your test needs referential integrity across tables, write the script — or generate each table separately and wire the foreign keys yourself.
You need it in CI. A committed faker.js script runs in your pipeline on every build. A browser tool is a manual step. For repeatable fixtures that live in the repo, the script wins.
You need custom distributions. Want 80% of users in one country and 20% split across three others? Want signup dates skewed toward the last 30 days? That's a few lines of code in a script and awkward-to-impossible in a point-and-click schema.
You need very large volumes. The free tier caps at 20,000 rows; Pro removes that cap. But if you're generating millions of rows for a load test, a script streaming to disk is the more sensible tool.
You need exotic formats. If the consumer wants Parquet or Avro, you're writing code regardless.
If you're comparing against hosted services, the trade-off is similar but the axis shifts: SaaS generators usually have richer type libraries and shareable schemas, but your schema travels over the network. The Mock Data Generator keeps the faker.js call stack on your machine, which is the whole point.
Edge cases worth knowing
A few things that bite people after the first successful generation:
- Dates as strings vs objects. JSON export gives you strings; if your app expects ISO 8601, check the format before you seed. CSV will always be strings, so downstream parsing is on you.
- Locale data is a Pro feature. The free tier's 15 field types cover the common cases. If you need names and addresses that look right for a specific country, that's the 30+ locale-aware field types on Pro.
- Email uniqueness. faker.js generates plausible emails, but with large row counts you can hit collisions. If your test asserts uniqueness, dedupe after generation or add an index column.
- Schema persistence. Free generation is stateless between sessions. Pro saves up to 20 schemas in IndexedDB, so your user-table schema is still there tomorrow.
- CSV quoting. Names with commas and addresses with newlines will break naive CSV parsers. The tool handles quoting on export; your import step still needs to respect it.
The short version
If you need realistic user rows fast, in a format you can hand to someone else, and you don't want your schema leaving your laptop, the browser tool is the shorter path. If you need relational fixtures, custom distributions, or CI integration, write the script — it's not much code and it lives with your tests.
Most teams I've seen end up with both: a script for the committed fixtures, and a browser tab for the one-off "I need 2,000 users in staging by lunch" moments. The Mock Data Generator covers the second case without an account, and the free tier's 20,000-row limit is more than enough for that job.
FAQ
Does the Mock Data Generator send my schema anywhere?
No. faker.js runs locally in the browser, so the schema you build and the rows you generate stay on your device. There's no upload step and no server round-trip. That's the main reason to use it over a hosted mock-data service when your schema mirrors a real table.
Can I generate related tables, like users and their orders?
Not as linked records in a single pass. The tool generates independent rows per schema, so foreign keys aren't wired automatically. Generate each table separately and connect the IDs yourself, or write a faker.js script if referential integrity is central to your test.
What export formats are available?
Free exports are JSON and CSV. Pro adds SQL INSERT statements and a multi-format ZIP export, which is useful when the frontend wants JSON and the database wants SQL from the same dataset.
How many rows can I generate for free?
Up to 20,000 rows per generation on the free tier, with 15 field types. Pro removes the row cap and unlocks 30+ field types including locale-specific data, plus schema saving in IndexedDB.
Is this a replacement for Mockaroo or similar services?
For most day-to-day needs, yes — you get realistic faker.js output without an account or an upload. Hosted services still have advantages in shareable schemas and some niche type libraries. If your schema contains internal field names or enum values, keeping it local is the safer default.
Do I need to install anything?
No install. Open the tool page, build a schema, generate, and download. The only thing you might want on hand is a text editor or database client for the exported file.