AWS Simple Queue Service (SQS), Simple Notification Service (SNS), and EventBridge are three powerful AWS services that have been designed to help businesses with their data processing and messaging needs. Each of these services has its own unique features and advantages, making them suitable for different use cases. SQS is a pull-based message queuing system, while SNS is a pub/sub service for instant, push-based message distribution to multiple subscribers. 

In this article, we will discuss the difference between SQS and SNS and EventBridge, how to use each of these services, and how they compare against each other.

What is AWS SQS?

Amazon SQS (Simple Queue Service) is a fully managed, reliable, and highly scalable message queuing service. It provides an easy way for applications to decouple and scale components that would otherwise be tightly coupled and difficult to scale. With SQS, producers can send messages to an SQS queue, and consumers can retrieve messages from the queue. SQS also supports message-level visibility, meaning that messages can be individually acknowledged or deleted.

SQS is ideal for decoupling applications and components that require asynchronous communication. For example, if your application needs to process a large set of data, you can use SQS to queue up the data and process it in the background.

SQS Main Concepts

SNS is a distributed and highly available queuing system that can scale up to millions of messages per second. Its main concepts include:

1. Queues – SQS queues are the basic structure that hold messages sent by producers and are consumed by consumers.

2. Messages – SQS messages are the actual data sent by producers and received by consumers.

3. Producers – Producers are the applications that send messages to SQS queues.

4. Consumers – Consumers are the applications that read and process messages from SQS queues.

5. Visibility Timeout – Visibility Timeout is the period of time during which a message is invisible to other consumers after it has been read and processed by a consumer.

6. Long Polling – Long Polling is a technique used to reduce the cost associated with polling SQS queues by requesting messages only when new messages arrive in the queue.

7. Dead Letter Queue – A Dead Letter Queue is a queue that receives messages that have failed delivery after several attempts.

8. Permissions – Permissions are used to control access to SQS queues and messages.

9. Encryption – SQS supports server-side encryption for messages using the AWS Key Management Service (KMS).

10. Monitoring – SQS provides metrics and alarms to monitor performance and detect problems in your application.

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What is AWS SNS?

Amazon SNS (Simple Notification Service) is a fully managed, highly available, and highly scalable push messaging service. It is used to send notifications to mobile devices, web browsers, or other applications. SNS provides a range of features such as topics, subscriptions, and message filtering.

SNS is ideal for applications that need to send real-time notifications or messages to a large number of subscribers. For example, if your application needs to send notifications to your customers, you can use SNS to do so.

SNS Main Concepts

Amazon SNS main concepts include:

  1. Topics – Topics are communication channels to which publishers send messages. Subscribers receive messages published to the topic.

  2. Publishers – Publishers (or producers) send messages to SNS topics. They don’t need to know who the subscribers are.

  3. Subscribers – Subscribers receive messages from topics. They can be SQS queues, Lambda functions, HTTPS endpoints, email addresses, or SMS numbers.

  4. Subscriptions – A subscription connects a topic to an endpoint (e.g., an SQS queue or Lambda). Each subscriber must confirm the subscription.

  5. Message Filtering – SNS supports attribute-based message filtering, allowing subscribers to receive only messages matching specific criteria.

  6. Fan-Out – SNS supports fan-out by delivering a single message to multiple endpoints in parallel, increasing message distribution efficiency.

  7. Delivery Policies – You can define retry behavior for message deliveries, including backoff strategies and maximum retry attempts.

  8. Dead Letter Queues (DLQs) – For subscription endpoints like Lambda or SQS, SNS can send undeliverable messages to a DLQ after multiple failed attempts.

What is AWS EventBridge?

Amazon EventBridge is a fully managed, serverless event bus service. It is used to send and receive events between applications, services, and servers. EventBridge supports a range of event sources and destinations, including AWS services, custom applications, SaaS applications, and third-party services.

EventBridge is ideal for applications that need to process events from multiple sources in real time. For example, if your application needs to process events from a variety of sources and publish them to multiple destinations, you can use EventBridge to do so.

EventBridge Main Concepts

The main concepts behind EventBridge are:

  1. Event Buses – Event buses receive events from different sources. There’s a default bus, custom buses, and a partner bus for SaaS integrations.

  2. Events – Events are JSON-formatted data records that describe a change in state or action (e.g., a new EC2 instance or a support ticket created).

  3. Event Sources – Sources can be AWS services, SaaS providers, or custom applications that generate events and push them to an EventBridge bus.

  4. Rules – Rules match incoming events based on patterns and determine where to route them (e.g., Lambda, SQS, Step Functions, or SNS).

  5. Targets – Targets are AWS services or resources that process the event. A single rule can have multiple targets.

  6. Event Patterns – Event patterns define filtering criteria that rules use to match events. Only matching events are sent to targets.

  7. Schema Registry – EventBridge can automatically discover and store event schemas, helping developers understand event structure and generate code bindings.

  8. Archive and Replay – EventBridge allows you to archive events for later auditing or debugging and replay them to reprocess or test your workflows.

AWS SQS vs SNS vs Eventbridge – When to Use What?

Let’s talk about the difference between SNS and SQS and EventBridge. All three are messaging services, but they serve different purposes. SQS is for decoupling with queues, SNS is for pub/sub fan-out messaging, and EventBridge is for advanced event routing and filtering. Choosing the right one depends on how your components communicate and how much control you need over event flow.

When to Use SQS

As we discussed above, SQS is ideal for applications that require asynchronous communication. It is also suitable for applications that need to process large amounts of data in the background.

  • Reliable 1:1 Asynchronous communication to decouple applications
  • Rate limit message consumption
  • Ordered message processing

When to Use SNS

SNS is ideal for applications that need to send real-time notifications or messages to a large number of subscribers. It is also suitable for applications that need to send push notifications to mobile devices, web browsers, or other applications.

  • Publish messages to many different subscribers with single action
  • High throughput and reliability for publishing and delivery
  • Many subscribers

When to Use EventBridge

EventBridge is ideal for applications that need to process events from multiple sources in real time and publish them to multiple destinations. It is also suitable for applications that need to integrate with a variety of services, applications, and servers.

  • Publish messages to many subscribers, using event data to match targets
  • Integration with other SaaS providers
  • Easily discover schemas
  • Regularly scheduled events using cron-like expression
  • Create one-time events

Schema Registry/Discovery

While SQS and SNS focus on delivering messages, EventBridge goes further by helping you understand the structure of those messages. That’s where the schema registry comes in. Built into EventBridge, it automatically discovers the format of incoming events, stores them, and versions each schema. This is especially useful when your team is consuming events from multiple producers—or when your events evolve over time and need strong validation. You can even generate code bindings for Java, Python, or TypeScript, reducing the need for manual parsing.

Third Party Integrations

One of the key advantages of EventBridge over SQS and SNS is its ability to integrate directly with external SaaS providers. Using partner event sources, EventBridge can receive events from platforms like Auth0, Zendesk, Datadog, and more—no polling or custom webhooks required. Once those events land in your event bus, you can route them to any AWS service, just like internal events. This gives EventBridge a unique edge in hybrid or SaaS-heavy architectures, enabling end-to-end automation across both AWS and third-party tools with minimal glue code.

Wrap Up

EventBridge vs SQS vs SNS are three powerful AWS services that have been designed to help businesses with their data processing and messaging needs. Each of these services has its own unique features and advantages, making them suitable for different use cases. When deciding which service to use, it is important to consider the data processing capabilities, cost structure, and scalability of each service. 

If your application requires asynchronous communication, SQS is the best choice. If your application needs to send real-time notifications or messages to a large number of subscribers, SNS is the right choice. Finally, if your application needs to process events from multiple sources in real time and publish them to multiple destinations, EventBridge is the optimal choice. 

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Frequently Asked Questions

Is SNS asynchronous or synchronous?

Amazon SNS (Simple Notification Service) is an asynchronous messaging service. Publishers send messages to an SNS topic without waiting for subscribers to process them. This allows systems to decouple and scale independently. Subscribers—such as Lambda functions, SQS queues, or HTTPS endpoints—receive and process messages at their own pace. Because it’s event-driven and non-blocking, SNS is ideal for real-time fan-out use cases like alerts, mobile notifications, and system integrations where immediate subscriber response isn’t required. Alternatives to AWS SQS include Kafka, RabbitMQ, Google Pub/Sub, Azure Service Bus, and Redis Streams—each offering different tradeoffs in durability, ordering, and real-time processing.

Is Kafka like SQS or SNS?

Kafka is more comparable to Amazon SQS in terms of message queueing, but with key differences. Kafka stores messages on disk for a configurable retention period and allows consumers to reprocess messages multiple times. SQS is a managed queue with at-least-once delivery but limited message retention and no message replay. SNS, by contrast, is a pub/sub service designed for immediate fan-out, more similar to Kafka’s topic-based model, but without persistent storage or consumer-managed offsets.

Can EventBridge trigger SNS?

Yes, EventBridge can trigger SNS. You can create a rule in EventBridge that matches certain event patterns and routes those events to an SNS topic as a target. This allows you to forward filtered or enriched events to mobile devices, email, HTTP endpoints, or other subscribers. It’s commonly used for system-wide event routing where EventBridge handles the filtering logic and SNS handles the message distribution across multiple subscribers or systems.

Should I use EventBridge or SQS?

Use EventBridge when you need event routing, filtering, schema validation, or integration with AWS services and SaaS platforms. It’s built for decoupled, event-driven architectures where events trigger actions across systems. Use SQS for point-to-point messaging, buffering, and reliable delivery between producers and consumers. SQS is better suited for queue-based task processing, while EventBridge excels at orchestrating loosely coupled event-driven workflows. They can also be combined: EventBridge routes, SQS buffers and delivers.

Why combine SNS and SQS?

Combining SNS and SQS gives you both fan-out and durability. SNS pushes messages to multiple subscribers simultaneously, but if a subscriber is down, messages may be lost. By subscribing SQS queues to an SNS topic, each queue reliably receives a copy of the message. This pattern ensures durable, decoupled delivery across services. Each queue can independently control message processing, retries, and throughput—making it ideal for scalable, fault-tolerant architectures.