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# Managing Subscriptions in Amazon SNS
![\[JavaScript code example that applies to Node.js execution\]](http://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/images/nodeicon.png)
**This Node.js code example shows:**
+ How to list all subscriptions to an Amazon SNS topic.
+ How to subscribe an email address, an application endpoint, or an AWS Lambda function to an Amazon SNS topic.
+ How to unsubscribe from Amazon SNS topics.
## The Scenario
In this example, you use a series of Node.js modules to publish notification messages to Amazon SNS topics. The Node.js modules use the SDK for JavaScript to manage topics using these methods of the `AWS.SNS` client class:
+ [https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/SNS.html#subscribe-property](https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/SNS.html#subscribe-property)
+ [https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/SNS.html#confirmSubscription-property](https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/SNS.html#confirmSubscription-property)
+ [https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/SNS.html#listSubscriptionsByTopic-property](https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/SNS.html#listSubscriptionsByTopic-property)
+ [https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/SNS.html#unsubscribe-property](https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/SNS.html#unsubscribe-property)
## Prerequisite Tasks
To set up and run this example, you must first complete these tasks:
+ Install Node.js. For more information about installing Node.js, see the [Node.js website](http://nodejs.org).
+ Create a shared configurations file with your user credentials. For more information about providing a credentials JSON file, see [Loading Credentials in Node.js from the Shared Credentials File](loading-node-credentials-shared.md).
## Listing Subscriptions to a Topic
In this example, use a Node.js module to list all subscriptions to an Amazon SNS topic. Create a Node.js module with the file name `sns_listsubscriptions.js`. Configure the SDK as previously shown.
Create an object containing the `TopicArn` parameter for the topic whose subscriptions you want to list. Pass the parameters to the `listSubscriptionsByTopic` method of the `AWS.SNS` client class. To call the `listSubscriptionsByTopic` method, create a promise for invoking an Amazon SNS service object, passing the parameters object. Then handle the `response` in the promise callback.
```
// Load the AWS SDK for Node.js
var AWS = require("aws-sdk");
// Set region
AWS.config.update({ region: "REGION" });
const params = {
TopicArn: "TOPIC_ARN",
};
// Create promise and SNS service object
var subslistPromise = new AWS.SNS({ apiVersion: "2010-03-31" })
.listSubscriptionsByTopic(params)
.promise();
// Handle promise's fulfilled/rejected states
subslistPromise
.then(function (data) {
console.log(data);
})
.catch(function (err) {
console.error(err, err.stack);
});
```
To run the example, type the following at the command line.
```
node sns_listsubscriptions.js
```
This sample code can be found [here on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/master/javascript/example_code/sns/sns_listsubscriptions.js).
## Subscribing an Email Address to a Topic
In this example, use a Node.js module to subscribe an email address so that it receives SMTP email messages from an Amazon SNS topic. Create a Node.js module with the file name `sns_subscribeemail.js`. Configure the SDK as previously shown.
Create an object containing the `Protocol` parameter to specify the `email` protocol, the `TopicArn` for the topic to subscribe to, and an email address as the message `Endpoint`. Pass the parameters to the `subscribe` method of the `AWS.SNS` client class. You can use the `subscribe` method to subscribe several different endpoints to an Amazon SNS topic, depending on the values used for parameters passed, as other examples in this topic will show.
To call the `subscribe` method, create a promise for invoking an Amazon SNS service object, passing the parameters object. Then handle the `response` in the promise callback.
```
// Load the AWS SDK for Node.js
var AWS = require("aws-sdk");
// Set region
AWS.config.update({ region: "REGION" });
// Create subscribe/email parameters
var params = {
Protocol: "EMAIL" /* required */,
TopicArn: "TOPIC_ARN" /* required */,
Endpoint: "EMAIL_ADDRESS",
};
// Create promise and SNS service object
var subscribePromise = new AWS.SNS({ apiVersion: "2010-03-31" })
.subscribe(params)
.promise();
// Handle promise's fulfilled/rejected states
subscribePromise
.then(function (data) {
console.log("Subscription ARN is " + data.SubscriptionArn);
})
.catch(function (err) {
console.error(err, err.stack);
});
```
To run the example, type the following at the command line.
```
node sns_subscribeemail.js
```
This sample code can be found [here on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/master/javascript/example_code/sns/sns_subscribeemail.js).
## Subscribing an Application Endpoint to a Topic
In this example, use a Node.js module to subscribe a mobile application endpoint so it receives notifications from an Amazon SNS topic. Create a Node.js module with the file name `sns_subscribeapp.js`. Configure the SDK as previously shown.
Create an object containing the `Protocol` parameter to specify the `application` protocol, the `TopicArn` for the topic to subscribe to, and the ARN of a mobile application endpoint for the `Endpoint` parameter. Pass the parameters to the `subscribe` method of the `AWS.SNS` client class.
To call the `subscribe` method, create a promise for invoking an Amazon SNS service object, passing the parameters object. Then handle the `response` in the promise callback.
```
// Load the AWS SDK for Node.js
var AWS = require("aws-sdk");
// Set region
AWS.config.update({ region: "REGION" });
// Create subscribe/email parameters
var params = {
Protocol: "application" /* required */,
TopicArn: "TOPIC_ARN" /* required */,
Endpoint: "MOBILE_ENDPOINT_ARN",
};
// Create promise and SNS service object
var subscribePromise = new AWS.SNS({ apiVersion: "2010-03-31" })
.subscribe(params)
.promise();
// Handle promise's fulfilled/rejected states
subscribePromise
.then(function (data) {
console.log("Subscription ARN is " + data.SubscriptionArn);
})
.catch(function (err) {
console.error(err, err.stack);
});
```
To run the example, type the following at the command line.
```
node sns_subscribeapp.js
```
This sample code can be found [here on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/master/javascript/example_code/sns/sns_subscribeapp.js).
## Subscribing a Lambda Function to a Topic
In this example, use a Node.js module to subscribe an AWS Lambda function so it receives notifications from an Amazon SNS topic. Create a Node.js module with the file name `sns_subscribelambda.js`. Configure the SDK as previously shown.
Create an object containing the `Protocol` parameter, specifying the `lambda` protocol, the `TopicArn` for the topic to subscribe to, and the ARN of an AWS Lambda function as the `Endpoint` parameter. Pass the parameters to the `subscribe` method of the `AWS.SNS` client class.
To call the `subscribe` method, create a promise for invoking an Amazon SNS service object, passing the parameters object. Then handle the `response` in the promise callback.
```
// Load the AWS SDK for Node.js
var AWS = require("aws-sdk");
// Set region
AWS.config.update({ region: "REGION" });
// Create subscribe/email parameters
var params = {
Protocol: "lambda" /* required */,
TopicArn: "TOPIC_ARN" /* required */,
Endpoint: "LAMBDA_FUNCTION_ARN",
};
// Create promise and SNS service object
var subscribePromise = new AWS.SNS({ apiVersion: "2010-03-31" })
.subscribe(params)
.promise();
// Handle promise's fulfilled/rejected states
subscribePromise
.then(function (data) {
console.log("Subscription ARN is " + data.SubscriptionArn);
})
.catch(function (err) {
console.error(err, err.stack);
});
```
To run the example, type the following at the command line.
```
node sns_subscribelambda.js
```
This sample code can be found [here on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/master/javascript/example_code/sns/sns_subscribelambda.js).
## Unsubscribing from a Topic
In this example, use a Node.js module to unsubscribe an Amazon SNS topic subscription. Create a Node.js module with the file name `sns_unsubscribe.js`. Configure the SDK as previously shown.
Create an object containing the `SubscriptionArn` parameter, specifying the ARN of the subscription to unsubscribe. Pass the parameters to the `unsubscribe` method of the `AWS.SNS` client class.
To call the `unsubscribe` method, create a promise for invoking an Amazon SNS service object, passing the parameters object. Then handle the `response` in the promise callback.
```
// Load the AWS SDK for Node.js
var AWS = require("aws-sdk");
// Set region
AWS.config.update({ region: "REGION" });
// Create promise and SNS service object
var subscribePromise = new AWS.SNS({ apiVersion: "2010-03-31" })
.unsubscribe({ SubscriptionArn: TOPIC_SUBSCRIPTION_ARN })
.promise();
// Handle promise's fulfilled/rejected states
subscribePromise
.then(function (data) {
console.log(data);
})
.catch(function (err) {
console.error(err, err.stack);
});
```
To run the example, type the following at the command line.
```
node sns_unsubscribe.js
```
This sample code can be found [here on GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/master/javascript/example_code/sns/sns_unsubscribe.js).