TL;DR — Stripe Payments

Design a payment processing platform similar to Stripe that enables merchants to accept online payments. The system must handle credit card tokenization, payment authorization and capture, webhook delivery for asynchronous events, and PCI DSS compliance while processing millions of transactions per day with exactly-once semantics. Key features: Tokenize credit card details into reusable payment tokens. Authorize, capture, and refund payments with idempotency keys.