Architect a high-throughput Order Processing Engine
Last updated: September 17, 2025
Quick Overview
Design a high-throughput order processing system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Zillow
September 17, 20255
5
3,102 solved
Design a high-throughput order processing system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
System design interviews at Zillow typically last 45-60 minutes. You are expected to drive the conversation, starting from requirements gathering through to a detailed architecture. The interviewer will evaluate your ability to handle ambiguity and make practical engineering decisions.
What the Interviewer Expects
- Clearly define functional and non-functional requirements
- Propose a reasonable high-level architecture with core components
- Choose appropriate data storage solutions with basic justification
- Discuss basic scaling strategies (horizontal scaling, caching)
- Identify potential bottlenecks and suggest simple solutions
Key Topics to Cover
How to Approach This
- Start by clarifying functional and non-functional requirements with the interviewer.
- Estimate the scale: QPS, storage, bandwidth. This drives your design decisions.
- Draw a high-level architecture first, then deep dive into 1-2 critical components.
- Discuss trade-offs explicitly (e.g., consistency vs availability, SQL vs NoSQL).
- Address failure scenarios, monitoring, and how the system handles 10x traffic spikes.
Possible Follow-up Questions
- How would you handle a region-wide outage?
- How would you implement rate limiting to protect the system?
- What monitoring and alerting would you set up on day one?
- What happens if one of your database nodes goes down?
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Requirements
Functional Requirements
- Order Submission: Users should be able to submit orders in real-time.
- Order Status Tracking: Users can check the status of their orders at any time.
- **Orde...
Capacity Estimation
Assuming we handle 1 million orders per day:
- Per Second Calculation: 1,000,000 orders/day / 86,400 seconds/day ≈ 11.57 orders/second.
- Peak Load Calculation: To account for peak times, let'...
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