Design a scalable Monitoring System
Last updated: April 22, 2026
Quick Overview
Design a scalable monitoring system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Booking.com
System Design
Software Engineer
Booking.com
April 22, 2026Software Engineer
System Design Round
System Design
Medium
271
8
3,990 solved
Design a scalable monitoring system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Booking.com asks this during the System Design Round 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
- 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
Partitioning and sharding strategies
High-level architecture and component design
Database selection and data modeling
Security and authentication
Caching strategies (local, distributed, CDN)
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?
- How would you handle a region-wide outage?
- What would the deployment pipeline look like for this system?
- How would you migrate from a monolithic to a microservices architecture?
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:
- Real-time monitoring of user interactions on Booking.com, including searches, bookings, and cancellations.
- Alerting system for anomalies like spikes in traffic o...
Capacity Estimation
- User Traffic:
- Assume Booking.com has around 500 million monthly active users.
- If each user generates an average of 5 requests per session, we can estimate:
- Daily requests = 500M us...
Submit Your Answer
Markdown supported