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AT&T·Software Engineer·Onsite - System Design / Architecture·Senior

Senior
Apr 2026

Summary

System design round for a software engineer role, just one question about building an emergency notification system. Not a lot of context given upfront so I had to do a lot of scoping myself.

Questions Asked (1)

Q1

Design a disaster and emergency notification system.

System DesignTechnical Trade-offsAdaptability & Ambiguity
Author's notes

Spent the first few minutes just trying to nail down requirements because this thing could go a hundred directions.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the scope: what types of disasters (natural, man-made), target population size, and delivery channels (SMS, voice, push, sirens). Then design a scalable, multi-channel system with high availability, focusing on trade-offs like latency vs. reliability and cost vs. coverage.

Pro tip: Emphasize the need for redundancy and failover across channels and regions, and discuss how to handle message prioritization and throttling to avoid network congestion during emergencies.

1. Clarify Requirements

Ask questions to understand scale (e.g., millions of users), latency requirements, types of alerts, and integration with existing telecom infrastructure.

2. High-Level Architecture

Outline core components: alert ingestion, processing, routing, and delivery via multiple channels (SMS, voice, push, cell broadcast). Include a geo-targeting service.

3. Deep Dive into Key Components

Detail the message queue, prioritization, and delivery mechanisms. Discuss how to ensure low latency and high throughput using distributed systems.

4. Address Reliability and Scalability

Explain redundancy, failover, and load balancing. Discuss how to handle spikes and ensure message delivery even under network stress.

5. Trade-offs and Considerations

Discuss trade-offs between cost, speed, and reliability. Mention security, privacy, and regulatory compliance (e.g., FCC, GDPR).

Key Points to Mention

  • Multi-channel delivery (SMS, voice, push, cell broadcast) with fallback mechanisms
  • Geo-targeting and location-based routing for precise alerts
  • Scalability and low-latency using distributed message queues (e.g., Kafka)
  • High availability and redundancy across data centers and networks
  • Prioritization and throttling to prevent network overload
  • Security, authentication, and compliance with regulations

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.