SAA-C03 Q469 · Serverless

Question

A company is building a serverless application to process orders from an ecommerce site. The application needs to handle bursts of traffic during peak usage hours and to maintain high availability. The orders must be processed asynchronously in the order the application receives them. Which solution will meet these requirements?

Accepted Answer

**Answer B: SQS FIFO queue + Lambda** satisfies every requirement:

1. **Serverless**: Both SQS and Lambda are fully managed, serverless services — no infrastructure to provision or manage.

2. **Asynchronous processing**: SQS is the quintessential AWS service for decoupling and asynchronous message processing. Orders are placed in the queue and processed independently by Lambda.

3. **Ordered processing (FIFO)**: The question explicitly states orders must be processed **in the order they are received**. SQS **FIFO** (First-In-First-Out) queues guarantee strict message ordering. This is the critical differentiator — standard queues do NOT guarantee order.

4. **Handle traffic bursts**: SQS acts as a **buffer** that absorbs spikes in traffic. Messages queue up during bursts and Lambda proce

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