Biometric Attendance System

Challenge

Eye hospital relied on manual staff logging and Excel formulas for attendance, overtime, and salary calculations.

Constraints

• —ZKTeco hardware deployment with SDK constraints
• —Web + Android access needed for hospital staff
• —30-day pay cycles with PL accrual rules
• —Maintenance coverage without an on-site IT team

Architecture

• •FastAPI backend with Supabase auth/storage
• •React admin portal with policy rules
• •Expo Android app for staff check-in/out
• •ZKTeco SDK integration for biometric events
• •Railway for worker processes, Vercel for admin web

Key Decisions

• •Separated device event ingestion from payroll rules to keep hardware failures from breaking payroll
• •Used configurable policy rules instead of hard-coded formulas

Impact

Automated salary cycle tracking, PL accrual, overtime, and deductions for 8+ employees with zero downtime since deployment.

Web + Android app. Login required.

Links

Stack