Architect a low-latency Authentication Engine
Last updated: November 8, 2025
Quick Overview
Design a low-latency authentication system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Anthropic
November 8, 202598
11
3,123 solved
Design a low-latency authentication system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
System design interviews at Anthropic typically last 45-60 minutes. You are expected to drive the conversation, starting from requirements gathering through to a detailed architecture. The interviewer will evaluate your ability to handle ambiguity and make practical engineering decisions.
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?
- What happens if one of your database nodes goes down?
- How do you ensure data consistency across multiple services?
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Requirements
Functional Requirements
- User Authentication: The system must authenticate users using various methods (password, OAuth, etc.).
- Session Management: It should manage user sessions secu...
Capacity Estimation
To estimate capacity, we consider the following:
- Peak Requests: Assume a peak of 1,000 requests per second (RPS) during heavy usage periods.
- Daily Requests: At peak, this translates to 1,0...