Design Chat Infrastructure for global users

Last updated: December 1, 2025

Quick Overview

Design a scalable chat system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.

NVIDIA
System Design
Software Engineer
NVIDIA
December 1, 2025
Software Engineer
System Design Round
System Design
Hard

49

10

131 solved


Design a scalable chat system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.

NVIDIA asks this during the System Design Round to assess your architectural thinking. They want to see how you decompose a complex problem, choose appropriate technologies, and reason about failure modes. Strong candidates proactively discuss monitoring, alerting, and operational concerns.

What the Interviewer Expects
  • Drive the design discussion proactively with minimal interviewer guidance
  • Perform detailed capacity estimation and use it to inform design decisions
  • Design for global scale with multi-region deployment and data consistency
  • Deep dive into 2-3 critical components with implementation-level detail
  • Address complex trade-offs: CAP theorem, eventual consistency, conflict resolution
  • Discuss operational excellence: deployment strategy, chaos engineering, SLOs/SLIs
  • Propose a phased rollout plan from MVP to full-scale system
Key Topics to Cover
API design and rate limiting
Failure handling and fault tolerance
High-level architecture and component design
Caching strategies (local, distributed, CDN)
Partitioning and sharding strategies
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
  • What monitoring and alerting would you set up on day one?
  • How would you implement rate limiting to protect the system?
  • How would you migrate from a monolithic to a microservices architecture?
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Sample Answer
Requirements Clarification

Before diving into the architecture, clarify the scope with the interviewer. For Chat Infrastructure for global users, key functional requirements inc...

Capacity Estimation

Estimate the scale to drive design decisions. Assume 100M DAU with an average of 10 actions per user per day = 1B requests/day ~ 12K QPS average, ~36K...


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