Microsoft OA 面试真题解析：Design a Notification System（通知系统设计）

Design a notification system that receives notification requests and sends notifications to users through phone or email.

The system should be scalable, highly available, and fault tolerant.

You may discuss the API and database schema in detail, or start with the high-level infrastructure components.

这道题考察的是高并发通知系统设计：客户端先把通知请求发给通知编排服务，再通过消息队列解耦发送流程，由后台 worker 异步消费并调用邮件或短信等发送通道。面试时重点要说明如何利用队列削峰、如何保证高可用和故障恢复，以及如何用数据库记录通知的创建、发送、失败等状态，便于审计和重试。