HR ↔ ERP Reconciliation Toolkit

The problem

HR data lived in one system; an ERP maintained its own mirrored copy for finance and payroll purposes. The two drifted — some of it real (a title change that hadn't synced), most of it cosmetic (phone number formatting, state abbreviations vs. full names, a supervisor name prefixed with an ID on one side and not the other). Every reconciliation cycle meant manually diffing ~22 fields across the full employee population in a spreadsheet, with no way to tell "known noise" from "an actual data problem" except by re-checking everything, every time.

What I built

A GUI tool that reads an export from each system, aligns their differently-named columns, and reconciles every matched employee field by field — with a persistent rules file for both value mappings (translate a known formatting difference to its equivalent) and acknowledged differences (mark a specific field on a specific employee as reviewed and expected, so it stops flagging on future runs).

• Output is a styled, multi-sheet Excel report: genuine unresolved breaks, acknowledged-but-different rows, employees missing from one side or the other, and a clean summary with a match rate.
• Reviewers can mark a difference as known directly from the results view, and it's suppressed on every subsequent run — the tool gets quieter over time instead of crying wolf on the same formatting quirks every cycle.

Why it mattered

It turned a recurring, error-prone manual audit into a five-minute repeatable process, and made "these two systems agree" something you could actually trust rather than something you hoped was true.