Two messaging services, one exam fork: notify many, or queue for one. Six questions on SNS, SQS and decoupling — CLF-C02, 2026 edition.
Try 6 free SNS and SQS questions in the exam's own style — every answer explained, no sign-up.
Straight to the 6 free questions ↓SNS and SQS are AWS’s core messaging services, and the exam tests them as one fork: notify many, or queue for one. Both exist to decouple application components so they do not depend on each other directly — but they do it in opposite ways.
If one service calls another directly and the second is busy or briefly down, work is lost or the caller stalls. A messaging service sits between them: the sender hands off a message and moves on, and the receiver deals with it when ready. That is decoupling, and it is the shared reason SNS and SQS exist.
Push to many, or pull from a queue. Almost every SNS/SQS question is deciding which of those a scenario describes.
Notice how they combine: SNS fans out, SQS buffers. Together they are the backbone of decoupled, resilient designs — which is exactly why the exam pairs them.
Answer each one before you reveal the explanation, and when you miss, read past the correct letter to why the other three fail. The distractors usually reverse push and pull, or offer an unrelated service (S3, Route 53) where messaging belongs. Keeping “notify many” and “queue for one” straight is the whole skill, and the reasoning below drills it.
What problem do both Amazon SNS and Amazon SQS help solve?
Both services let one part of an application communicate with another without a direct, tight connection — if one side is busy or briefly down, messages are not lost. Why not the others: encryption is KMS, cheap file storage is S3, and DNS is Route 53. Decoupling components is the shared purpose of SNS and SQS.
In Amazon SNS, what happens when a message is published to a topic?
SNS is publish/subscribe: a message sent to a topic is pushed out to every subscriber — a fan-out. Why not the others: waiting for a single consumer to pull it describes a queue (SQS). SNS does not store messages indefinitely or discard them. One message, many subscribers, is the SNS model.
In Amazon SQS, how is a message typically consumed?
SQS is a queue: messages wait until a consumer pulls one, processes it, and deletes it. Why not the others: broadcasting to all consumers is publish/subscribe (SNS). SQS does not send email, and messages are meant to be processed and removed, not kept forever. Pull-and-process is the SQS model.
What is the key difference between Amazon SNS and Amazon SQS?
SNS pushes each message out to all subscribers; SQS stores messages for a consumer to pull when ready. Why not the others: the descriptions are not reversed (SNS is the push/pub-sub one), they are not identical, and neither handles files or DNS. Push to many versus pull from a queue is the distinction.
An order service creates work faster than the processing service can handle during traffic spikes. What can sit between them so no work is lost?
An SQS queue absorbs the bursts — messages wait safely until the processing service pulls them, so nothing is dropped during a spike. Why not the others: SNS fans out and does not buffer for a single slow consumer, a direct call couples the two services and can overload the slow one, and S3 is object storage, not a work queue. Buffering with a queue is SQS.
A company wants a single event to trigger several independent processes at once. Which is a common pattern?
The SNS-to-SQS fan-out pattern publishes one message to an SNS topic, which delivers a copy to several SQS queues, each feeding an independent process. Why not the others: a single SQS queue gives a message to one consumer, not several independent ones; S3 and Route 53 are unrelated. Fan-out with SNS plus SQS is the standard pattern.
That is exactly how every question in the course works — answer, explanation, why-not. The real set continues in the practice player: 10 free questions, no sign-up.
Continue with the 10 free questions →The exam does not test whether you recognise a term — it tests whether you can rule out three plausible answers under time pressure. That is what the explanations above are for, and there are 390 more questions built exactly like them.
Collecting questions yourself
Practising with a system
Straight into the player. No account, no email.
Updated for CLF-C02 (July 2026). The sample questions above are our own work in the style of the exam — not real exam items. The exam itself is set and marked by the certification body.