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
System Design
Software Engineer
Anthropic
November 8, 2025
Software Engineer
System Design Round
System Design
Easy

98

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
Caching strategies (local, distributed, CDN)
Database selection and data modeling
Partitioning and sharding strategies
Consistency models and replication
High-level architecture and component design
Security and authentication
How to Approach This
  1. Start by clarifying functional and non-functional requirements with the interviewer.
  2. Estimate the scale: QPS, storage, bandwidth. This drives your design decisions.
  3. Draw a high-level architecture first, then deep dive into 1-2 critical components.
  4. Discuss trade-offs explicitly (e.g., consistency vs availability, SQL vs NoSQL).
  5. 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?
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
Requirements

Functional Requirements

  1. User Authentication: The system must authenticate users using various methods (password, OAuth, etc.).
  2. 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...

Submit Your Answer
Markdown supported

Related Questions