- A
Amazon SNS
Why wrong: SNS is a pub/sub notification service for pushing messages to multiple subscribers simultaneously. It does not store messages for later processing — if a subscriber is unavailable, the message is lost. SQS is the correct choice for durable buffering.
- B
Amazon SQS
SQS is a durable message queue that stores messages until they are processed. The intake API enqueues orders, and the processing service dequeues and processes them at its own pace. Messages persist even if the processor is temporarily unavailable.
- C
Amazon EventBridge
Why wrong: EventBridge is an event bus that routes events between services. While it can decouple components, it does not buffer messages for slow consumers the way SQS does.
- D
AWS Step Functions
Why wrong: Step Functions orchestrates multi-step workflows. It does not act as a buffer queue between a fast producer and a slow consumer.
Quick Answer
Amazon SQS is the correct choice because it decouples the API from the processing service by acting as a durable, fully managed message buffer. When the order intake API receives a burst of orders during a flash sale, it can instantly push each order as a message into an SQS queue, and the downstream processing service can then poll and consume those messages at its own pace, preventing the API from being overwhelmed and ensuring no orders are lost. On the AWS Certified Cloud Practitioner CLF-C02 exam, this scenario tests your understanding of decoupling architectures and the specific role of SQS as a queue-based integration pattern; a common trap is to confuse SQS with Amazon SNS (a pub/sub notification service) or Amazon Kinesis (for real-time streaming). Remember the memory tip: “SQS = Queue to Smooth Spikes” — think of the queue as a shock absorber that lets the API run fast while the processor runs slow.
CLF-C02 Cloud Technology and Services Practice Question
This CLF-C02 practice question tests your understanding of cloud technology and services. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A retail company's order processing system receives large bursts of orders during flash sales. The order intake API gets overwhelmed because it directly calls a downstream processing service that is slower. The company wants to decouple the API from the processing service so orders are not lost during spikes. Which AWS service should they use?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Amazon SQS
Amazon SQS (Simple Queue Service) is the correct choice because it provides a fully managed message queue that decouples the order intake API from the downstream processing service. When the API receives a burst of orders, it can immediately push each order message into an SQS queue, and the processing service can poll and consume messages at its own pace, ensuring no orders are lost even during traffic spikes.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Amazon SNS
Why it's wrong here
SNS is a pub/sub notification service for pushing messages to multiple subscribers simultaneously. It does not store messages for later processing — if a subscriber is unavailable, the message is lost. SQS is the correct choice for durable buffering.
- ✓
Amazon SQS
Why this is correct
SQS is a durable message queue that stores messages until they are processed. The intake API enqueues orders, and the processing service dequeues and processes them at its own pace. Messages persist even if the processor is temporarily unavailable.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Amazon EventBridge
Why it's wrong here
EventBridge is an event bus that routes events between services. While it can decouple components, it does not buffer messages for slow consumers the way SQS does.
- ✗
AWS Step Functions
Why it's wrong here
Step Functions orchestrates multi-step workflows. It does not act as a buffer queue between a fast producer and a slow consumer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse SNS (push-based pub/sub) with SQS (pull-based queue), assuming any decoupling service works the same, but SNS cannot buffer messages or allow the consumer to control the consumption rate, making it unsuitable for handling bursts from a slower downstream service.
Detailed technical explanation
How to think about this question
SQS uses a distributed message queue with a default retention period of 4 days (configurable up to 14 days) and supports both standard queues (high throughput, at-least-once delivery) and FIFO queues (exactly-once processing, limited to 300 transactions per second). Under the hood, the API sends a message via the SQS SendMessage API, which stores the message redundantly across multiple Availability Zones, and the processing service polls using ReceiveMessage with a configurable visibility timeout to prevent duplicate processing.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this CLF-C02 question test?
Cloud Technology and Services — This question tests Cloud Technology and Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Amazon SQS — Amazon SQS (Simple Queue Service) is the correct choice because it provides a fully managed message queue that decouples the order intake API from the downstream processing service. When the API receives a burst of orders, it can immediately push each order message into an SQS queue, and the processing service can poll and consume messages at its own pace, ensuring no orders are lost even during traffic spikes.
What should I do if I get this CLF-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 11, 2026
This CLF-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CLF-C02 exam.
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