Build a low-latency Notification Pipeline
Last updated: November 23, 2025
Quick Overview
Design a low-latency notification system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
DE Shaw
November 23, 202510
3
2,908 solved
Design a low-latency notification system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
This is a common system design question asked during Onsite at DE Shaw. The interviewer expects you to demonstrate your ability to design large-scale distributed systems, make well-reasoned trade-offs, and communicate your thought process clearly. DE Shaw values engineers who can think about scalability from day one.
What the Interviewer Expects
- Systematically gather requirements and estimate capacity (QPS, storage, bandwidth)
- Design a scalable architecture with clear component responsibilities
- Make well-reasoned database and caching decisions with trade-off analysis
- Address consistency vs availability trade-offs specific to the use case
- Discuss partitioning strategy, replication, and data modeling
- Cover failure handling, monitoring, and alerting strategies
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 schema migrations with zero downtime?
- How would you implement rate limiting to protect the system?
- How would you migrate from a monolithic to a microservices architecture?
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Requirements
- Functional Requirements:
- The system should support sending notifications to millions of users in real-time.
- Notification types include alerts (urgent), messages (standard), and rem...
Capacity Estimation
- Request Per Second (QPS) Calculation:
Assuming peak load is 10 million notifications per second and each notification is sent to an average of 10 users,
QPS = 10 million notifications/se...
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