Design a high-throughput Authentication System
Last updated: June 2, 2026
Quick Overview
Design a high-throughput authentication system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Palantir
June 2, 202636
10
1,611 solved
Design a high-throughput authentication system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
This is a common system design question asked during Technical Screen at Palantir. The interviewer expects you to demonstrate your ability to design large-scale distributed systems, make well-reasoned trade-offs, and communicate your thought process clearly. Palantir values engineers who can think about scalability from day one.
What the Interviewer Expects
- Systematically gather requirements and estimate capacity (QPS, storage, bandwidth)
- Design a scalable architecture with clear component responsibilities
- Make well-reasoned database and caching decisions with trade-off analysis
- Address consistency vs availability trade-offs specific to the use case
- Discuss partitioning strategy, replication, and data modeling
- Cover failure handling, monitoring, and alerting strategies
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?
- How would you handle schema migrations with zero downtime?
- What would the deployment pipeline look like for this system?
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Requirements
Functional Requirements:
- User Authentication: Support for login/logout operations, including multi-factor authentication (MFA).
- User Management: APIs for user registration, password ...
Capacity Estimation
Assuming we are handling an average of 10,000 QPS:
- Peak Load: 10,000 QPS translates to about 864 million requests per day.
- User Sessions: If we estimate that each user remains logged in fo...
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