Design a one-to-one chat system
Company: Anthropic
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Technical Screen
Overview: This question evaluates a candidate's ability to design scalable, real-time one-to-one messaging systems, testing competencies in transport choice for server→client push, presence detection, durable message storage and delivery semantics, ordering, idempotency, and technology trade-offs between short-lived online state and durable pipelines.