A performance reporting platform
Tier-1 Nigerian bank
About 1,800 relationship managers each spent roughly an hour a day assembling performance spreadsheets by hand. I designed and built the platform that replaced that work - reporting, dashboards, credit monitoring, and budgeting - and it removed on the order of 468,000 hours of manual effort a year. It settled at around 1,900 unique users a week.
I built it outside the remit of the role I held at the time, which is the part I am actually proud of: nobody asked for it.