Architect a scalable Caching Engine
Last updated: June 9, 2026
Quick Overview
Design a scalable caching system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Compass
June 9, 202610
5
4,392 solved
Design a scalable caching system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
This fundamentals question from Compass's System Design Round tests whether you can reason about software design at a deep level. The interviewer expects discussion of maintainability, testability, and operational considerations.
What the Interviewer Expects
- Apply engineering principles to a realistic design scenario
- Discuss trade-offs between different approaches with concrete examples
- Demonstrate understanding of testability, maintainability, and extensibility
- Connect theoretical concepts to production engineering practices
- Discuss how the approach scales with team and codebase size
Key Topics to Cover
How to Approach This
- Apply SOLID principles. Single Responsibility makes code testable, Open/Closed makes it extensible.
- Choose data structures based on access patterns, not familiarity.
- Prefer immutable data and message passing over shared mutable state for concurrency.
- Design APIs with RESTful conventions, versioning, meaningful errors, and pagination from day one.
Possible Follow-up Questions
- What are the security implications of this design?
- How would you handle backward compatibility?
- What testing strategy would you use for this component?
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Core Design Principles
For designing a scalable caching engine for Compass, we should apply the following core design principles:
- Separation of Concerns: By modularizing the caching logic from application logic, we ...
Architecture
For the caching engine, I propose a microservices architecture where the caching service operates independently from other services. Key architectural components include:
- Distributed Cache: We...
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