Data Generator

A small web app that generates Croatian test data with one click: IBANs, OIBs (national ID numbers) and personal names. It is meant for filling forms and test databases, not for anything that needs real people or real accounts.

The interface is available in Croatian (default) and English, with light and dark themes. The theme switch (in the header, or the footer on phones) has three options: Light, Dark, and Auto (the default), which follows your device's light/dark setting even while the page is open. Both the theme and language choices are remembered. It works on phones as well as desktop.

What it generates

Generator	Details
IBAN	Croatian IBANs (HR…) for a bank you pick from five major banks, or a random one (the default); the bank-code caption always names the bank used. The IBAN check digits and the bank's own account control digit are both calculated correctly, so the number passes strict validators, but it is not a real account. The number is colour-coded and measured: country and check digits, bank code (with the bank's name underneath), account number.
OIB	11-digit OIBs with a valid check digit.
Names	1–50 Croatian first and last names. Generated by AI; if the AI is unavailable, they come from a built-in list of about 120 first names and 110 surnames, and a notice says so.

Every value can be copied with one click: use the Copy button or click the number itself. For names there are also Copy all (one name per line) and CSV (all names on one line, separated by commas) buttons, a "Copies as" switch to choose First Last or Last First for every copy action, and a button per name (click a first or last name on its own to copy just that part).

Keyboard shortcuts: G generates a new value, C copies it (or copies all on the Names page). They are ignored while you are typing in a field, and Ctrl/Cmd+C still works as usual.

Running it locally

You need Node.js installed.

npm install
npm run dev

Then open http://localhost:3000.

AI-generated names (optional)

IBAN and OIB need no setup. For AI names, create a .env.local file in the project root with a Google Gemini API key:

GEMINI_API_KEY=your-key-here

Without a key, the Names page still works using the built-in list.

Optional settings in the same file:

Variable	Default	Purpose
GEMINI_MODEL	gemini-3.5-flash-lite	Model tried first
GEMINI_FALLBACK_MODEL	gemini-3.5-flash	Used if the first one fails or is overloaded

Google retires and renames models regularly. If AI names stop working, check the server log for a "no longer available" message and set the variables above to a current model.

Commands

npm run dev     # development server
npm run build   # production build
npm run start   # run the production build
npm run lint    # check the code with ESLint

Built with

Next.js (App Router), React, TypeScript and Tailwind CSS.

Working on the code with Claude Code? See CLAUDE.md. Planned improvements and open questions are in BACKLOG.md.