Most people with premium credit cards leave $500-1000/year on the table in unused credits, offers, and wrong-card swipes. CardStack connects to your actual spending via Plaid and uses AI to show you exactly what you're missing — in dollars, not percentages. Track every credit. Auto-enroll Amex and Chase offers. Know which card to use at checkout. See your real ROI per card. Built for Amex, Chase, and premium card power users who are tired of managing their wallet in a spreadsheet.