Notenbuch

The school ran on paper timetables and a shared inbox. Notenbuch gives the office a schedule grid by teacher and room, every student a record with lessons and invoices, and parents a phone page that shows the next lesson and lets them reschedule it once.

React and Node on Postgres, SEPA invoicing through a bank API, hosted on a single Hetzner box because that is what a music school can afford. Still running, three major versions later.