Pongdang is a browser app for class-based studios: dance, music and art schools, yoga and pilates studios, and martial arts schools. There's no signup and nothing to install; you can also add it to your home screen.
Owners create their own classes and monthly N-session passes, and unused sessions carry over automatically. Students check in by scanning one printed QR poster with their phone camera (no app needed), and the session is deducted from their own pass. Kids without phones use a QR card or a kiosk number.
It also tracks absences and makeups, records tuition (record only; Pongdang doesn't process payments), and prepares low-pass and unpaid reminders that you send from your own phone by KakaoTalk, WhatsApp or SMS. Export to Excel at any time, and lock admin screens with a PIN.
Data stays on your device in the browser, with encrypted backups you keep yourself. Korean and English UI. Made by a solo maker; feedback from studio owners is very welcome.
Small dance, music and art studios I looked at still track monthly passes, carryover and makeups on paper or in spreadsheets, and most studio software asks for accounts and setup first. I wanted something an owner could open in a browser and use the same day, with student data staying on their own device. I'm a solo maker and I'm looking for feedback from studio owners.