I built a free QR code generator with Next.js and Supabase — here's what I learned

I was looking for a simple QR code generator for a side project. Everything I found was either full of ads, paywalled, or just ugly.
So I built QR Einfach from scratch.
The tech stack

Next.js for the frontend and routing
Supabase for auth and database
QR code generation directly in the browser (no server-side rendering needed)

What it supports

URL, WiFi, vCard, WhatsApp, PDF, Google Reviews
Bulk QR code generation
Export as PNG, SVG, ZIP, CSV or PDF

What I learned
Generating QR codes client-side is fast and keeps the server load minimal. The tricky part was bulk export — packaging multiple SVGs into a ZIP on the browser side without a backend call.
Supabase made auth surprisingly easy. I had login, user sessions and a basic dashboard running in a day.
Try it
https://www.qreinfach.de/en
Feedback welcome — especially if you spot something weird on mobile!