Design a large-scale Authentication Platform
Last updated: October 16, 2025
Quick Overview
Design a multi-tenant authentication system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Capital One
October 16, 202547
5
1,873 solved
Design a multi-tenant authentication system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Capital One asks this during the System Design Round to assess your depth in software engineering. They want to see understanding of design patterns, system architecture, and the trade-offs involved in different technical approaches.
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
- How would you handle backward compatibility?
- How would you document this for other engineers?
- How would you measure the performance of this component in production?
- What are the security implications of this design?
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
Core Design Principles
For the design of a large-scale authentication platform at Capital One, the following core design principles are critical:
- Separation of Concerns: This principle allows us to modularize the au...
Architecture
The architecture of the authentication platform will adopt a microservices approach. Key components include:
- API Gateway: Acts as a single entry point for all authentication requests, routing ...
Submit Your Answer
