Payroll Calendar Validation Tool
A Python-based tool that proactively identified and resolved payroll configuration errors — reducing error rates from 71% to 1% across 170+ clients.
📌 Overview
In 2019, over 70% of all system-related errors were tied to misconfigured pay calendars. I developed a lightweight automation tool that now scans over 500 calendars weekly, flags issues in seconds, and distributes tailored error reports to client teams — eliminating manual QA and drastically improving system integrity.
📺 Live Demo
Watch a brief walkthrough of the tool in action. Including how calendars are validated, how errors are flagged, and what emails look like.
💡 My Role
- Designed and implemented the full solution using Python and SQL
- Collaborated with internal teams to define business rules and exceptions
- Created a web version (via Streamlit + AWS) to allow self-service validation
- Maintained tool across multiple years with continuous enhancements
⚙️ What It Does
- Validates over 20,000 calendar rows weekly
- Applies 15+ custom business rules to check cutoff dates, pay frequency, and configuration flags
- Produces detailed CSV error reports that drive Power BI dashboards for tracking and analysis.
- Sends personalized emails to responsible client team leads
- Maintains backup copies of calendars for rollback and auditing
📉 Key Results
Metric | Before | After | Change |
Payroll errors caused by calendars | 71% | 1% | 🔻 -70 pts |
Calendars validated per week | ~50 (manual) | 500+ (automated) | 🔼 10x |
Clients covered | ~20 | 170+ | 🔼 8x |
Validation time | ~30 mins | < 30 seconds | ⏱️ 98% time savings |
🌐 Bonus Feature: Web App
In 2025, I built a web-based version of the tool using Streamlit. It allows any user to upload an Excel calendar and instantly receive a validation report, using the same business rules as the backend tool.
🧠 Tech Stack
- Python (
pandas,numpy,datetime,openpyxl) - SQL (manual CSV pulls for testing, Oracle backend)
- Streamlit (web version)
- AWS (EC2, S3)
- pywin32 (email alerts)
- Power BI (dashboards)
🔗 Project Files / Links
🙌 Why This Matters
Calendar validation is’nt glamorous, but errors disrupt payroll, damage trust, and waste hours. I built this tool to quietly solve a loud problem. It now runs weekly without fail, improving accuracy across hundreds of clients, and freeing up my team to focus on higher-value work.