SNS notification types (email, SMS, Lambda) in AWS - Step-by-Step Execution

Process Flow - SNS notification types (email, SMS, Lambda)

SNS Topic Created

↓

Subscribe Email

→Subscribe SMS

↓

Email Endpoint

↓

Publish Message to Topic

↓

SNS Sends Notification to All Subscribers

↓

Email Received, SMS Received, Lambda Invoked

SNS topic has subscribers of different types (email, SMS, Lambda). When a message is published, SNS sends notifications to all subscribers according to their type.

Execution Sample

AWS

Create SNS topic
Subscribe email endpoint
Subscribe SMS number
Subscribe Lambda function
Publish message to topic

This sequence creates an SNS topic, adds email, SMS, and Lambda subscribers, then publishes a message triggering notifications.

Process Table

Step	Action	Target	Result	Notification Sent
1	Create SNS Topic	MyTopic	Topic Created	No
2	Subscribe	Email [e-mail]	Subscription Pending Confirmation	No
3	Subscribe	SMS [phone]	Subscription Confirmed	No
4	Subscribe	Lambda Function ARN	Subscription Confirmed	No
5	Email User Confirms Subscription	[e-mail]	Subscription Confirmed	No
6	Publish Message	MyTopic	Message Published	Yes: Email, SMS, Lambda
7	SNS Sends Email	[e-mail]	Email Delivered	Yes
8	SNS Sends SMS	[phone]	SMS Delivered	Yes
9	SNS Invokes Lambda	Lambda Function	Lambda Executed	Yes
10	End	-	All Notifications Sent	No

💡 All subscribers confirmed and message published; notifications sent to all.

Status Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	After Step 5	After Step 6	Final
SNS Topic	None	Created	Created	Created	Created	Created	Created
Email Subscription	None	Pending	Pending	Pending	Confirmed	Confirmed	Confirmed
SMS Subscription	None	None	Confirmed	Confirmed	Confirmed	Confirmed	Confirmed
Lambda Subscription	None	None	None	Confirmed	Confirmed	Confirmed	Confirmed
Message Published	No	No	No	No	No	Yes	Yes
Notifications Sent	No	No	No	No	No	Yes	Yes

Key Moments - 3 Insights

Why does the email subscription show 'Pending' before confirmation?

Email subscriptions require the user to confirm by clicking a link. Until confirmed (see Step 5), SNS does not send notifications to that email.

Why are SMS and Lambda subscriptions confirmed immediately?

SMS and Lambda subscriptions do not require user confirmation, so SNS marks them as confirmed right after subscription (Steps 3 and 4).

When does SNS send notifications to subscribers?

SNS sends notifications only after a message is published to the topic and the subscriber is confirmed (Step 6 triggers sending in Steps 7-9).

Visual Quiz - 3 Questions

Look at the execution table, what is the status of the email subscription at Step 3?

A Confirmed

B None

C Pending Confirmation

D Unsubscribed

💡 Hint

Check the 'Result' column at Step 3 in the execution_table.

At which step does SNS send notifications to all subscribers?

A Step 6

B Step 5

C Step 7

D Step 10

💡 Hint

Look for 'Message Published' and 'Notifications Sent' in the execution_table.

If the email user never confirms subscription, what changes in the execution table?

A Email subscription becomes 'Confirmed' automatically

B Email subscription stays 'Pending', no email sent

C SNS sends email anyway

D Lambda subscription fails

💡 Hint

Refer to the 'Email Subscription' variable in variable_tracker and Step 5 in execution_table.

Concept Snapshot

SNS Topic holds subscribers of types: Email, SMS, Lambda.
Email requires user confirmation before receiving messages.
SMS and Lambda subscriptions confirm immediately.
Publishing a message sends notifications to all confirmed subscribers.
SNS handles delivery according to subscriber type.

Full Transcript

This visual execution traces how AWS SNS handles different notification types: email, SMS, and Lambda. First, an SNS topic is created. Then, subscribers are added: an email address, a phone number for SMS, and a Lambda function. Email subscriptions require the user to confirm by clicking a link, so initially, the email subscription is pending. SMS and Lambda subscriptions confirm immediately. When a message is published to the topic, SNS sends notifications only to confirmed subscribers. The email user receives an email after confirmation, SMS receives a text message, and the Lambda function is invoked. This process ensures reliable delivery tailored to each subscriber type.