Architect a low-latency Rate Limiting Engine
Last updated: December 30, 2025
Quick Overview
Design a low-latency rate limiting system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Uber
December 30, 2025133
5
3,753 solved
Design a low-latency rate limiting system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Uber asks this during the Technical Screen to assess your architectural thinking. They want to see how you decompose a complex problem, choose appropriate technologies, and reason about failure modes. Strong candidates proactively discuss monitoring, alerting, and operational concerns.
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 optimize costs as the system scales?
- What would the deployment pipeline look like for this 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
- Rate Limiting: The system should allow a configurable number of requests per user/IP per time window (e.g., 100 requests per minute).
- Dynamic Configuration: A...
Capacity Estimation
Assuming Uber handles around 5 billion requests per day:
- Peak Load Estimation: If we assume peak load is 10x the average, that would be about 58,000 requests per second.
- **Rate Limiting Window...
Submit Your Answer
