AWS (Amazon Web Services) SNS VS SQS

Are you confused between the AWS SNS and AWS SQS? If yes, here is the best guide to help you. This insightful article covers complete details on the comparison between the AWS SNS and AWS SQS. By the end of this guide, you will be able to easily find what AWS Tool is best suited for your business.

Introduction

The messaging service plays an important role in enabling the machines and software to communicate and exchange information. Whether it is an end device, software, or a cloud-based application, we can easily share the data across the machines and software using the Messaging Service.

If you are looking forward to exploring the AWS Messaging services, SNS, and SQS can be good options for you. In this article, we will learn how to choose the right AWS Messaging Service.

What is AWS SNS?

SNS means the AWS Simple Notification Service (SNS) which allows communication between distributed applications and services. We can broadcast messages to multiple subscribers in real time. This is due to the fact that It operates on a publish-subscribe model in which the publisher sends the message and the subscriber receives them.

You can use it for various purposes such as pushing out critical notifications to end-users or updating various components of a microservices architecture simultaneously. Hence, It provides a simple way to communicate through scalable and versatile messaging solutions.

What is AWS SQS?

Amazon Simple Queue Service (SQS) is based on a fully managed message queuing system that allows the components of a distributed application to communicate with each other. SQS operates on a queue-based model in which messages are sent and stored in a queue and then processed by consumers.

It has asynchronous communication which means that the sender and receiver entities are independent of each other. Thus, they do not need to be simultaneously active at the time of exchanging information. This enhances the fault tolerance and scalability of applications so that they can handle variable workloads with reliable delivery of messages. Now, let us see the difference between these two AWS services.

AWS SNS vs AWS SQS: Key differences

Feature	AWS SNS	AWS SQS
Communication Model	It uses the Push based service in which messages are forwarded directly to subscribed consumers	It uses the Poll-based model which stores the message queue and is processed by a single consumer
Use Case	Broadcasting messages to multiple endpoints	Decoupled message processing
Message Format	It supports various formats	It has a generic message format
Delivery Time	Real-time delivery is supported in SNS	It has an Asynchronous delivery in which queue that stores the message.
Subscription	Subscribers receive every message	Each message goes to a single consumer
Message Retention	It does not store messages and delivers immediate	Message is stored until successfully processed
Scaling	It has Vertical scaling which is suitable for low-latency	It supports Horizontal scaling to handle the changing workloads
Batching	SNS works on a single message at a time. Hence, batching is not possible.	It can batch multiple messages into a single batch.

Advantages of AWS SNS

• It provides real-time communication: SNS allows us to deliver the message in real-time. This is suitable for cases when we need to quickly notify all the end-subscribed end-points or applications.
• It can scale to large users: If the workload of the messaging system changes, SNS can easily handle them. It provides vertical scaling through which a large number of messages can be easily handled.
• It supports integration with AWS Services: We can send a message in Application-to-Application like AWS Lambda, Amazon SQS, Amazon Kinesis Data Firehose, and AWS Event Fork Pipelines. Also, we can share the message to Application-to-Person destinations like SMS, Email, In-App notification, and AWS Chatbot.

Advantages of AWS SQS

• It process messages in Asynchronously:The sender in SQS does not need to wait for the response from the receiver. He can continuously send the message which is stored in the message queue. Thus, SQS has asycnrounous communication.
• It guarantees the message delivery: Since the messages are stored in the message queue until they are processed. This ensures that the message is delivered to the endpoint.
• It makes the sender and receiver independent: The sender and receiver do not depend on each other. They work as separate entities within the messaging systems. So, the SQS provides the decoupled processing.

When Should I Choose AWS SNS?

• The number of subscribers is large and you need to publish the messages to all the end-points.
• You want to send the messages to the Application-to-Person destination such as SMS, Email, or app notifications.
• You want to instantly send the message to multiple subscribers at the same time.

When Should I Choose AWS SQS?

• Your messaging system has only a single consumer who can receive the message.
• You need error handling and persistence. Or, if you want to successful message delivery to the receiver.
• The message processing needs to be batched and the sender-receiver should operate independently.

Cost of AWS SNS

AWS provides a free tier as well as quote-based pricing for the SNS Messaging service. Since it is available as a cloud-based service, you need to pay only for the resources that you use. The SNS charges are billed at the end of the month on the basis of usage. Also, charges are based on the number of requests made to the SNS Service.

For example, the free tier of the mobile push notifications includes 1 million notifications and its pricing starts at $0.50 per million notifications. The details of SNS Pricing based on the end-point are available at the official website at “https://aws.amazon.com/sns/pricing/”.

Cost of AWS SQS

Just like the AWS SNS, the SQS is a cloud-based service in which the bill is issued on the basis of the number of requests made to the service. It also has a free tier service in which the first 2 million requests per month are free. The pricing of the SQS Service also depends on the type of queue used in the system. The queue can be standard or FIFO Queue. The cost of the SQS Service can be known through the quote from the official website. For detailed information about the pricing, you can visit the official website at “https://aws.amazon.com/sqs/pricing/”.

Conclusion

SQS and SNS both are messaging services that allow us to send and receive information through the system components. The Simple Notification Service(SNS) uses a publish-subscribe model in which the publisher sends the message which is instantly received by the consumers. On the other hand, the Simple Queuing System uses a message Queue in which the messages are stored when sent by the publisher. Then, they are processed by the consumers. After gaining a clear understanding of both messaging services, we can easily identify the best messaging service according to our business requirements.

Frequently Asked Questions

How does the AWS SNS filter messages?

SNS allows the subscribers to set the policies for the incoming messages so that they receive the message only up to the specific criteria. Hence, the messaging service becomes more targeted using AWS SNS.

Is AWS SNS secure for messaging services?

AWS SNS protects the data using server-side encryption using AWS Key Management Service. It also allows the users to set up a private connection between the SNS and Virtual Private Cloud.

What is the Message Lifecyle in the AWS SQS?

SQS messaging has a simple messaging process in which the Sender Component sends information to the message queue. Then, the Consumer fetches the message from the queue. This is the time when the visibility period starts. After that, the receiver processes the message and deletes the message from the queue once the visibility period of the message ends.

How do the AWS SQS and SNS differ from the AWS MQ?

SQS and SNS are the messaging services of AWS. On the other hand, AWS MQ is the Message Broker service. It acts as a middleware between the sender and receiver in the messaging system. It provides messaging protocols such as Advanced Message Queueing Protocol (AMQP), Message Queuing Telemetry Transport (MQTT), WebSocket, etc.

What are the Attributes of an AWS SQS Message?

The message in the SQS system includes the metadata such as timestamps, geospatial data, signatures, and identifiers and attributes. Each message can have up to 10 attributes. The message consumers use these attributes to handle the message as per their preference.