Design a Payment System
Hard · System Design · about 45 minutes
Asked at Airbnb, Amazon, Block (Square), Coinbase, PayPal, Robinhood, Shopify, Stripe, Goldman Sachs, JPMorgan Chase, Intuit, Visa, Capital One, Plaid, Ramp, Chime, SoFi, Affirm, Klarna, Revolut, American Express, Toast, Rippling, Gusto, Brex, Mercury, Kraken.
Design the backend that processes payments for an e-commerce marketplace: charge buyers through external payment processors, pay out sellers, and keep an accurate ledger. Money must never be lost or double-charged.