A custom HRMS that turns fingerprint punches into payslips

The office runs two ZKTeco biometric readers — an MB20-VL at the entrance (fingerprint + face) and a K70 at the exit (fingerprint) — while the HRMS lives on a remote cloud server that, for security, cannot open connections into the office network. The two machines had opposite capabilities: one could call home, the other couldn’t speak to the internet at all — and its log was 88% full, at 176,000 records. On top of that, payroll had been built before any attendance data existed, so every figure was keyed in by hand.

Software Alliance made both devices feed a single attendance record, then closed the loop all the way to payroll:

• Attendance integration. Implemented the ZKTeco ADMS / iClock push protocol server-side so the MB20-VL streams punches over HTTPS in real time; for the pull-only K70, built a Python LAN bridge (pyzk) on an in-office PC that forwards to the same ingestion endpoint, with a 10-minute catch-up as a safety net. Per-device identity mapping, idempotent de-duplication and timezone-honest logic keep it clean and self-healing.
• Payroll automation. A payroll engine reads a month of attendance and produces each payslip — pro-rated working days, absence and lateness deductions, overtime and paid leave — with every number a traceable line item.
• Employee self-service portal. Attendance calendar, payslips, and leave / expense / missed-punch requests that route to HR and write back into attendance, separated from the admin by role-based policies.
• Production hardening. A shared validation rule across 20+ modules, duplicate and date-range guards, and a reusable redirect concern — each landing with automated tests through two full QA passes.

Fingerprint to payslip, with no manual keying:

• 176,000+ punches processed into one attendance record per person, worked hours derived automatically against each shift.
• A month of payslips generated in one action, every figure tracing back to a punch.
• 20+ HR modules — employees, shifts, leaves, payroll, recruitment, appraisals and more — regression-proofed with a growing test suite and zero-downtime deploys.