System Design Interview Practice

Practise system design interviews step by step: clarify requirements, estimate, design and defend trade-offs across 6 problems, from rate limiters to payments.

• Payment Platform at 50,000 TPS — Expert. Design a payment platform that processes 50,000 transactions per second.
• ShopFlow Checkout — Hard. Design the checkout flow for an e-commerce platform with carts, payments, inventory and order confirmation.
• Flash Sale Inventory — Expert. Design a system that sells 10,000 limited items to 2 million users in the first minute of a sale — without overselling.
• Notification Platform — Medium. Design a service that sends email, SMS and push notifications for many internal teams, reliably and without spamming users.
• Ride Dispatch — Hard. Design the system that matches riders to nearby drivers in real time across many cities.
• Distributed Rate Limiter — Medium. Design a rate limiter for a public API used by 100,000 customers, enforced across many gateway instances.