SNS notification types (email, SMS, Lambda) in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

SNS Email Subscription Behavior

When an AWS SNS topic has an email subscription, what happens immediately after a message is published to the topic?

A The message is sent directly to the email address without any confirmation.

B The email address receives a confirmation request and must confirm before receiving messages.

C The message is stored in an S3 bucket linked to the email subscription.

D The email subscription triggers a Lambda function to send the message.

💡 Hint

Think about how SNS ensures the email owner wants to receive messages.

SNS requires email subscriptions to be confirmed by the recipient before messages are delivered. This prevents unwanted emails.

❓ service_behavior

intermediate

SNS SMS Message Delivery Limits

What is a key limitation when sending SMS messages via AWS SNS?

A SNS can send SMS messages only within the same AWS region as the topic.

B SNS requires a Lambda function to process SMS messages before sending.

C SNS SMS messages have a maximum size of 140 bytes and may be split if longer.

D SNS SMS messages can only be sent to phone numbers verified in the AWS account.

💡 Hint

Consider SMS message size limits in telecom.

SMS messages have size limits (usually 140 bytes). SNS splits longer messages into multiple SMS segments automatically.

❓ Architecture

advanced

SNS with Lambda Subscription Behavior

Which statement correctly describes what happens when an SNS topic has a Lambda function subscribed and a message is published?

A SNS invokes the Lambda function asynchronously immediately after publishing the message.

B SNS invokes the Lambda function synchronously and waits for the function to complete before returning.

C SNS stores the message in S3 and triggers Lambda asynchronously after a delay.

D SNS requires the Lambda function to poll the topic to receive messages.

💡 Hint

Think about how SNS triggers Lambda functions.

SNS invokes Lambda functions asynchronously immediately after a message is published to the topic.

❓ security

advanced

Securing SNS Email Subscriptions

Which method best protects an SNS email subscription from unauthorized subscription requests?

A Configure SNS to send messages only to verified email addresses in AWS SES.

B Enable server-side encryption on the SNS topic.

C Restrict SNS topic access using IAM policies only.

D Use subscription confirmation emails that require user action to activate.

💡 Hint

Think about how SNS confirms email ownership.

Subscription confirmation emails require the recipient to confirm the subscription, preventing unauthorized subscriptions.

✅ Best Practice

expert

Designing Reliable SNS Notifications with Multiple Protocols

You want to ensure that a critical alert message sent via SNS reaches both an email recipient and triggers a Lambda function. Which design approach ensures the highest reliability and fault tolerance?

A Create one SNS topic with both email and Lambda subscriptions; rely on SNS retry policies for failures.

B Create separate SNS topics for email and Lambda; publish the message twice from your application.

C Use one SNS topic with email subscription only; Lambda polls the email inbox for messages.

D Send the email and invoke the Lambda function directly from your application, bypassing SNS.

💡 Hint

Consider SNS built-in retry and fan-out capabilities.

Using one SNS topic with multiple subscriptions leverages SNS's fan-out and retry mechanisms, improving reliability and simplifying architecture.