Stripe says 2.9% + $0.30. I was actually paying 4.7%. The problem? Stripe's dashboard shows gross volume, not your real fee rate. International cards, FX, refunds, and small transactions quietly push it higher — but you never see it in one place. Stripe Fee Auditor fixes this: upload your Balance CSV and get your real effective rate, monthly trends, fee drivers, and savings opportunities. Without connecting your Stripe account. No OAuth. No signup. No raw CSV stored.