Architect a low-latency Feed Generation Engine
Last updated: November 24, 2025
Quick Overview
Design a low-latency feed generation system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Uber
November 24, 202598
3
593 solved
Design a low-latency feed generation system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
ML system design at Uber goes beyond model selection. This System Design Round question evaluates your ability to design end-to-end ML pipelines, from data collection to model serving, while considering production constraints like latency and reliability.
What the Interviewer Expects
- Define clear ML objectives with appropriate loss functions and metrics
- Design a comprehensive feature engineering pipeline
- Discuss model selection with trade-offs (complexity vs interpretability vs latency)
- Plan online and offline evaluation strategies including A/B testing
- Address serving infrastructure: batch vs real-time, latency requirements
- Consider data quality, labeling strategy, and feedback loops
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 10x increase in prediction requests?
- How would you handle the cold start problem?
- How would you run A/B tests on different model versions?
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Requirements
Functional Requirements
- Real-time Feed Generation: The system must generate personalized feeds for users within milliseconds based on their recent activities, preferences, and location.
- **...
Capacity Estimation
Assuming Uber has 100 million active users and each user requests a feed update 10 times per day:
- Total Requests per Day: 100 million users * 10 requests = 1 billion requests.
- **Requests per...
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