Design a event-driven Recommendation System
Last updated: July 8, 2025
Quick Overview
Design a event-driven recommendation system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Waymo
July 8, 2025555
11
3,083 solved
Design a event-driven recommendation system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
This is a common system design question asked during System Design Round at Waymo. 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. Waymo 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 optimize costs as the system scales?
- What would the deployment pipeline look like for this system?
- How would you implement rate limiting to protect the system?
Practice a Similar Problem on Codemia
Solve a related problem with our interactive workspace, get AI feedback, and view detailed solutions.
Solve on CodemiaSample Answer
Requirements
- Functional Requirements:
- The system should provide personalized recommendations for users based on their historical interactions and preferences.
- Real-time processing of user events to u...
Capacity Estimation
- Estimating QPS:
- Assume Waymo has 1 million active users.
- Each user generates 10 events per minute (e.g., ride requests, feedback submissions).
- This results in approximately 10 millio...
Submit Your Answer
