The problem it closes
Duplicate queue numbers and queue jumping because the only record is a paper book.
The paper queue book at the front desk is the most common source of friction in a traditional clinic: duplicate numbers, queue jumping, and staff forced to remember who arrived first. HatraKu replaces it with one live list that the front desk, the practitioner, and the patient all see.
Patients can register themselves by scanning the daily QR code posted in the waiting room, or be registered by staff at the desk. A number is only issued after staff press Confirm Payment, so calling order follows payment order rather than sign-up order. That feels fair to the patient who has been waiting since morning.
When a number must change, the system shifts the others automatically: no duplicates, no gaps. The waiting-room board shows the current number in large type and announces it aloud in Indonesian.