Design a One-to-One Chat System
Company: Anthropic
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Onsite
Overview: Design durable one-to-one messaging with ordered history, offline recovery, multi-device delivery, and optional receipt state. Important concerns include idempotent sends, authorization, partitioning, backpressure, reconnect synchronization, retention, and honest failure semantics.