Design Recommendation Infrastructure for real-time analytics

Last updated: January 17, 2026

Quick Overview

Design a real-time recommendation system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.

Cockroach Labs
Software Engineering Fundamentals
Software Engineer
Cockroach Labs
January 17, 2026
Software Engineer
Technical Screen
Software Engineering Fundamentals
Medium

32

3

1,762 solved


Design a real-time recommendation system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.

Software engineering fundamentals questions at Cockroach Labs test your understanding of core CS concepts and their practical application. This Technical Screen question evaluates how you apply engineering principles to build maintainable, scalable software.

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
SOLID principles
Performance optimization
Code review best practices
CI/CD pipelines
Version control and branching strategies
How to Approach This
  1. Apply SOLID principles. Single Responsibility makes code testable, Open/Closed makes it extensible.
  2. Choose data structures based on access patterns, not familiarity.
  3. Prefer immutable data and message passing over shared mutable state for concurrency.
  4. Design APIs with RESTful conventions, versioning, meaningful errors, and pagination from day one.
Possible Follow-up Questions
  • How would this design change if the team size doubled?
  • What are the security implications of this design?
  • What testing strategy would you use for this component?
Practice a Similar Problem on Codemia

Solve a related problem with our interactive workspace, get AI feedback, and view detailed solutions.

Solve on Codemia
Sample Answer
Core Principles

Start by identifying which engineering principles are most relevant: **SOLID Principles**: Single Responsibility (one reason to change), Open/Closed ...

Design Approach

**API Design**: Define clear interfaces before implementation. Use RESTful conventions for HTTP APIs. Version your APIs from the start. Return meaning...


Submit Your Answer
Markdown supported

Related Questions