Show Dev: I built a fast offline calculator hub with Next.js & Cloudflare

Sergey Sereda — Tue, 10 Feb 2026 21:17:47 +0000

Hi everyone! I’m a full-stack engineer and like many of you, I’m tired of “utility” websites that are bloated with ads, cookies, painfully slow, and overloaded with trackers.

So I decided to build qalc.ai — a clean, lightning-fast hub for calculators and practical tools that actually respect the user experience.

It works fully offline after the first load, has no intrusive pop-ups, and only a single small banner ad that can be closed for the entire day without interrupting anything.

Originally, I built most of these tools for myself — things I was constantly calculating or Googling while working with finance, crypto, and everyday conversions. Over time, it turned into a growing collection of calculators and productivity tools that I now keep expanding.

The Tech Stack 🛠️

To keep it fast, scalable, and SEO-friendly:
Frontend: Next.js (App Router) for SSR + ISR
Styling: Tailwind CSS with shadcn UI
Edge & SEO: Cloudflare caching + IndexNow for instant indexing
Logic: Pure TypeScript (no heavy backend)

UX Philosophy:
Works offline
No clutter
No annoying ads
No tracking
Just input → result

I’d Love Your Feedback 🎤

I’d really appreciate a technical roast or constructive feedback:
Performance: Does it feel instant?
UI/UX: Is navigation clear?
Features: What calculator or tool do you Google most often?

👉 https://qalc.ai

Thanks for checking it out — happy hacking! 🚀

DEV Community: Sergey Sereda

Show Dev: I built a fast offline calculator hub with Next.js & Cloudflare