AWS SNS - Sending Notifications the Smart Way

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Arjit Sharma
02 Mins

Need to send alerts, emails, or trigger backend processes when something happens in your app? Simple Notification Service (SNS) is your tool.

What Is SNS?

AWS SNS is a fully managed (publish/subscribe) messaging service. It allows you to send messages(notifications) to subscribers using multiple protocols such as email, SMS, Lambda etc.

When to Use SNS:

  • Sending notifications or alerts to users
  • You want to broadcast messages to multiple systems
  • Decoupling application components

How SNS Works

  1. Publishers send messages to SNS topics.
  2. SNS forwards the message to all subscribers of that topic.
  3. Subscribers receive the message via their preferred protocol - email, SMS, Lambda, SQS, HTTP, etc.

Key Concepts in SNS (Quick Reference)

ConceptDescription
TopicA channel where messages are sent (like a mailing list)
SubscriberAnything that receives messages (email, Lambda, etc.)
PublishSending a message to a topic
MessageThe content you’re sending
Message AttributesOptional metadata attached to the message

Example - Email Notification on User Signup

Let’s say you want to notify your team every time a new user signs up:

Step 1: Create a Topic

  • Go to the SNS Console → Create Topic.
  • Choose Standard Topic (or FIFO if you need strict ordering).
  • Give it a name.

Step 2: Add Subscribers

  • After the topic is created, click Create Subscription.
  • Set protocol to Email.
  • Enter your team’s email address.
  • Confirm the subscription via the confirmation email SNS sends.

Step 3: Automatically Publish a Message from Lambda

Whenever a new user signs up, trigger a Lambda function that publishes a message to the SNS topic. Here’s how your Lambda function might look:

const AWS = require('aws-sdk');
const sns = new AWS.SNS();

exports.handler = async (event) => {
  const user = event; // e.g., { username: 'jdoe', email: 'jdoe@example.com' }

  const params = {
    TopicArn: process.env.TOPIC_ARN, // Set in Lambda environment variables
    Message: `🎉 New user signed up:\nUsername: ${user.username}\nEmail: ${user.email}`,
    Subject: '🚀 New User Registration',
  };

  await sns.publish(params).promise();
};
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