Amazon SNS VS SQS

When it comes to developing software, Amazon Web Services (AWS) corresponds to a developer’s dream toolkit. It assists in the development of dependable, high-performing apps that can manage heavy workloads. Amazon Simple Notification Service (SNS) and Amazon Simple Queue Service (SQS) are two of the many services that AWS provides. These tools, which operate similarly to communication wizards, assist communication between various app components. Consider SNS as an instant messenger that can send messages to multiple recipients at once. However, SQS acts as a careful messenger, ensuring that messages are delivered in a well-organized manner even during congested times.

AWS SNS(Simple Notification Service)

AWS Simple Notification Service (SNS) is a fully managed notification service provided by Amazon Web Services(AWS). The motive behind developing SNS is to help developers build scalable, reliable, and cost-effective applications by providing them with a simple and easy-to-configure notification system without worrying about the underlying infrastructure. AWS SNS works on the publisher-subscriber(pub-sub) model. With AWS SNS you can send notifications to various channels like mobile Devices (Android, iOS), Email, SMS, HTTP/HTTPS endpoints, AWS Simple Queue Service(SQS), etc.

AWS SQS(Simple Queue Service)

AWS Simple Queue Service (AWS SQS) is a messaging queue service provided by Amazon Web Services(AWS). SQS supports the decoupling and asynchronous communication between various systems within a distributed architecture. The motive behind the SQS is to make a reliable and scalable method for transmitting messages between dissimilar software components. In Simpler Terms, AWS SQS works like temporary waiting lines for the messages, where messages are added to the queue by the sending component and users retrieve these messages for their further processing. So SQS temporarily stores the messages and separates the message generation and message consumption phase. Thus promoting asynchronous and decoupled communication between different parts of an application.

Difference Between AWS SNS Vs AWS SQS

Topic	AWS SNS	AWS SQS
Communication Type	Publisher/Subscriber Here messages/notifications are published to topics by notification producers and subscribers which have subscribed to this topic can instantly receive the messages	Point-to-Point Here messages/ notifications are produced by producers and stored in the temporary queue and consumers can independently retrieve those messages/notifications.
Message Delivery	SNS follows push mechanism where subscribers receives messages/notifications instantly.	SQS follows pull mechanism where messages/notifications are being pulled from the queue.
Message Retrieval	Subscribers/endpoints will recieve the messages/notifications instantly without any active retrieval	Consumers have to poll the queue independently to retrieve the messages/notifications
Message Retension	Messages/Notifications delivered in real time so do not persist messages/notifications	Messages/Notifications not deliverd in real time to consumers so it provide persistance,it will store the messages until completely processed or explicitly deleted
Use Case	Ideal for scenarios where instant messages/notifications delivery required to single or multiple receipients.ex:- mobile push notifications,broadcasting messages.	Ideal for scenarios where different parts of a system need to work independently.ex:-load balancing,task offloading etc.
Fan Out	SNS allows single message/notification to be delivered to multiple subscribers instantly without the need for the individual configurations for each receipient.	SQS doesn’t directly support fan-out,to achieve fan-out in SQS need to configure seperate queue for each consumer and required additional configuration for message/notification duplication.
Retry Mechanism	Incase of failed delivery to subscribers it automatically retries.	Here Consumers are responsible for handling retries.
Scaling Mechanism	It scales with the number of subscribers.	It scales with the volume of the messages.

How To Choose Between AWS SNS And AWS SQS?

Selecting between Amazon SNS and SQS requires you to make a decision regarding the management of your messages. Amazon SNS functions as a broadcast system, making it ideal for quickly alerting a sizable audience to significant updates. As an alternative, Amazon SQS serves as a message queue, delivering data to various application components in an orderly and independent manner. Amazon SNS is the best option if instantaneous broadcasting to a large audience is your top priority. But if you would rather have a system that thoughtfully distributes messages to different areas of your application in a structured fashion, Amazon SQS is the best option.
In short, it comes down to whether you need to handle messages within your application in an organised manner (SQS) or make large announcements quickly (SNS).

Pros And Cons Of AWS SNS

Pros Of AWS SNS

• Perfect for situations where sending an instant message to one or more recipients is necessary (ex:- push notifications).
• Provides real-time message delivery via a push mechanism.
• It is appropriate for situations where the number of subscribers is increasing because it scales with the number of subscribers.

Cons Of AWS SNS

• Because messages are not saved for later retrieval, there is no message persistence.
• AWS SNS charges per message that effects in the cost increase when the message volumes are more.
• AWS SNS doesn’t support delayed message delivery which effects in precising the timing of message delivery.
• SNS comes with limited customization of delivery retries for the messages.

Pros And Cons Of AWS SQS

Pros Of AWS SQS

• Suitable for situations in which various components of a system must function separately (such as load balancing and task offloading).
• Supports a pull mechanism so users can get messages whenever it’s convenient for them.
• Message persistence is offered until it is explicitly removed or fully processed.

Cons Of AWS SQS

• If a message delivery attempt is unsuccessful, consumers are in responsible for handling retries.
• AWS SQS has limit on Message size, Its maximum limit is 256KB per message which is challenging when dealing with larger payloads.
• SQS follows FIFO (Frist-In-First-Out) option, ensuring strict message ordering which increase the complexity and impact on overall system performance.

In Conclusion, there are differences between the functions of AWS SNS and AWS SQS when it comes to message management in a system. SNS is the best option if you need to easily broadcast messages to different parts of your system. It guarantees that messages are sent to several subscribers immediately without requiring them to actively fetch them. Conversely, SQS is the answer if you need a more regulated and autonomous processing method. It facilitates efficient handling and scalability by allowing components to operate independently by pulling messages at their own speed. Select SNS for a more extensive message distribution and SQS for an asynchronous, more customised communication setup.

Amazon SNS And SQS – FAQs

How AWS SNS Able To Handle The Message Deivery To Multiple Subscribers?

AWS SNS works on the pub-sub(Publisher-Subscriber) model so it enables the single message to be delivered instantly to multiple subscribers without any individual configuration on each consumer side.

Is AWS SNS Deliver Messages To Mobile Devices Running On Different OS?

Yes, With the help of AWS SNS you can send push notifications to both Android and iOS devices.

Which Channels Does AWS SNS Supports For Message Delivery?

AWS SNS supports emails, SMS, push -notifications, HTTP/HTTPS end points and also provide integration with different AWS services like AWS SQS etc.

How Does AWS SQS Ensures The Message Ordering?

AWS SQS functions on the FIFO(First-In First-Out) principle that ensures the message ordering.

Can I Prioritize Certain Messages Over Others In AWS SQS?

Message prioritisation is not supported by SQS by default. Nonetheless, you can use multiple queues with varying processing priorities to implement your own prioritisation logic.

Can We Use AWS SQS And AWS SNS Together In A Single System?

Yes, to build dependable and scalable distributed systems, AWS SNS and SQS are frequently used in combination.