Every day, millions of people search for tiny jobs: merge two PDFs, compress a photo for a form, check an electricity bill, convert JPG to PNG. Most tool sites make them upload private files to a stranger's server, watch ads, and sign up for the privilege.

I wanted the opposite, so I built RozKaTool (https://asaantools.pages.dev/) — 40+ tools that run 100% client-side. The server only serves static files. All processing happens in the visitor's browser with JavaScript.

What is inside

  • PDF tools — merge, split, compress, rotate, JPG↔PDF, page numbers, watermarks (built on pdf-lib and PDF.js)
  • Image tools — compressor, resizer, cropper, format converters, passport photo maker, colour picker, Instagram grid splitter (Canvas API does the heavy lifting)
  • Calculators for Pakistan — electricity (bijli) bill with current slabs, salary tax, zakat — plus universal ones: age, BMI, EMI, percentage
  • Utilities — a real speed test, QR generator, word counter, password generator, unit converter

Three lessons from building it

1. Client-side is a feature, not a limitation.
"Your file never leaves your device" is the strongest trust line a tools site can have — and it costs nothing in server bills. Hosting is a static site on Cloudflare Pages; the marginal cost per user is effectively zero.

2. Local intent beats generic volume.
The most-used tools are not the glamorous ones. They are the bijli bill calculator during billing week and the salary tax calculator when a new budget lands. Tools that match a specific country's real life win loyal users that generic converters never keep.

3. Ship small, ship daily.
The site started with a handful of tools. Adding two or three small, finished tools at a time — each one tested live before the next — grew it to 40 without ever breaking what already worked. A tool that exists and works beats a perfect roadmap.

Try it / build on it

The site is live and free, no sign-up: https://asaantools.pages.dev/
The code lives on GitHub in the asaantools repo, and the tool pages are plain HTML/CSS/JS — view source is the documentation.

If you build tools for your own country's everyday headaches — the bill, the tax slab, the form photo — I would bet on that over the tenth generic AI wrapper. Local problems are global lessons.

RozKaTool — 40+ free online tools: https://asaantools.pages.dev/