Question 249 of 988
CLF-C02 Cloud Technology and Services Practice Question
A company is building a microservices application on AWS. The application consists of multiple independent services that need to communicate asynchronously. When an order is placed, the order service must send a notification to the inventory service, the shipping service, and the analytics service simultaneously. The company wants a fully managed, durable, and scalable messaging service that supports a fan-out pattern where a single message can be delivered to multiple subscribers. Which AWS service should the company use to meet these requirements?
⚠ Common exam trap
Watch out — candidates often confuse SQS (point-to-point queuing) with SNS (pub/sub fan-out), mistakenly thinking SQS can deliver to multiple consumers by using multiple queues, but SNS is the correct service for simultaneous, multi-subscriber delivery without polling.
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 Simple Notification Service (SNS)
Amazon Simple Notification Service (SNS) is a fully managed pub/sub messaging service that supports fan-out, where a single message published to a topic is delivered to multiple subscribers (e.g., SQS queues, Lambda functions, HTTP endpoints) simultaneously. It is durable (persists messages across AZs) and scales automatically to handle high throughput, making it ideal for the asynchronous notification requirements of the order, inventory, shipping, and analytics services.
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 Simple Queue Service (SQS)
Why it's wrong here
Amazon SQS is a message queuing service that enables decoupled communication between application components, but it is designed for point-to-point messaging. While you can configure SQS queues as subscribers to an SNS topic to achieve fan-out, SQS alone does not support sending a single message to multiple subscribers simultaneously.
When this WOULD be correct
A company needs a fully managed, durable, and scalable messaging service for decoupling application components where each message must be processed by exactly one consumer (e.g., order processing tasks). The requirement is for point-to-point asynchronous communication, not fan-out.
- ✓
Amazon Simple Notification Service (SNS)
Why this is correct
Amazon SNS is a fully managed pub/sub messaging service that supports the fan-out pattern. It can send a single message to multiple subscribers, including other AWS services like Lambda, SQS, and HTTP/S endpoints, making it the ideal choice for this requirement.
- ✗
Amazon Kinesis Data Streams
Why it's wrong here
Amazon Kinesis Data Streams is designed for real-time streaming of large-scale data, such as log data or clickstreams. It can support multiple consumers through enhanced fan-out, but it is overkill for a simple notification scenario and adds unnecessary complexity and cost.
When this WOULD be correct
A company needs to ingest and process real-time clickstream data from multiple web applications, where each record must be processed by multiple consumers in order (e.g., for analytics, fraud detection, and archiving). Kinesis Data Streams would be correct because it provides ordered, replayable data streams with multiple consumer applications.
- ✗
AWS Step Functions
Why it's wrong here
AWS Step Functions is a serverless orchestration service that lets you coordinate multiple AWS services into a workflow. It is not a messaging service and does not provide the pub/sub capability needed to distribute a single message to multiple subscribers.
When this WOULD be correct
A company needs to coordinate a multi-step order processing workflow that involves conditional logic, error handling, and sequential or parallel execution of tasks (e.g., validate order, charge payment, update inventory). Step Functions would be the correct choice for orchestrating such a workflow.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The CLF-C02 exam frequently reuses these exact scenarios with slightly different constraints.
✓Amazon Simple Notification Service (SNS)Correct answer▾
Why this is correct
Amazon SNS is a fully managed pub/sub messaging service that supports the fan-out pattern. It can send a single message to multiple subscribers, including other AWS services like Lambda, SQS, and HTTP/S endpoints, making it the ideal choice for this requirement.
✗Amazon Simple Queue Service (SQS)Wrong answer — click to see why▾
Why this is wrong here
Amazon SQS is a message queue service that supports point-to-point messaging, not a fan-out pattern. It cannot deliver a single message to multiple subscribers simultaneously; each message is consumed by only one consumer from a queue.
★ When this WOULD be the correct answer
A company needs a fully managed, durable, and scalable messaging service for decoupling application components where each message must be processed by exactly one consumer (e.g., order processing tasks). The requirement is for point-to-point asynchronous communication, not fan-out.
Why candidates choose this
Candidates may confuse SQS with SNS because both are messaging services, and they might think SQS can handle multiple consumers by using multiple queues, overlooking the need for a built-in fan-out mechanism.
✗Amazon Kinesis Data StreamsWrong answer — click to see why▾
Why this is wrong here
Amazon Kinesis Data Streams is designed for real-time streaming of large data volumes, not for simple fan-out messaging. It requires consumers to manage their own checkpointing and does not natively push messages to multiple subscribers; instead, consumers poll the stream.
★ When this WOULD be the correct answer
A company needs to ingest and process real-time clickstream data from multiple web applications, where each record must be processed by multiple consumers in order (e.g., for analytics, fraud detection, and archiving). Kinesis Data Streams would be correct because it provides ordered, replayable data streams with multiple consumer applications.
Why candidates choose this
Candidates may confuse Kinesis Data Streams with a messaging service that supports fan-out, or they may think that because it can have multiple consumers, it is suitable for asynchronous notification delivery.
✗AWS Step FunctionsWrong answer — click to see why▾
Why this is wrong here
AWS Step Functions is a serverless orchestration service for coordinating multiple AWS services into workflows, not a messaging service for fan-out message delivery. It does not natively support broadcasting a single message to multiple subscribers asynchronously.
★ When this WOULD be the correct answer
A company needs to coordinate a multi-step order processing workflow that involves conditional logic, error handling, and sequential or parallel execution of tasks (e.g., validate order, charge payment, update inventory). Step Functions would be the correct choice for orchestrating such a workflow.
Why candidates choose this
Candidates may confuse Step Functions' ability to invoke multiple services in parallel with the fan-out messaging pattern, not realizing that Step Functions is for workflow orchestration, not durable message broadcasting.
Analysis generated from the official CLF-C02blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
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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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