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

When deciding between AWS SQS (Simple Queue Service), SNS (Simple Notification Service), and EventBridge, it’s essential to understand the use cases and strengths of each service. Here’s a detailed comparison to help determine when to use what:

AWS SQS (Simple Queue Service)

Use Case: Message Queuing

  • Scenario: Use SQS when you need to decouple and scale microservices, distributed systems, and serverless applications.
  • Features:
    • Message Queuing: SQS stores messages until they are processed and deleted, ensuring that each message is processed at least once.
    • Decoupling: It helps to decouple application components, allowing each to process messages independently.
    • Visibility Timeout: Prevents other consumers from processing a message while it’s being worked on by another consumer.
    • Types:
      • Standard Queue: Offers maximum throughput, best-effort ordering, and at-least-once delivery.
      • FIFO Queue: Guarantees that messages are processed exactly once, in the exact order that they are sent.
  • Ideal For: Use cases requiring reliable, asynchronous communication between distributed components, such as order processing systems, task queues, and job dispatchers.

AWS SNS (Simple Notification Service)

Use Case: Pub/Sub Messaging

  • Scenario: Use SNS when you need to send messages to multiple subscribers, such as fan-out scenarios, mobile push notifications, and email notifications.
  • Features:
    • Topic-Based Pub/Sub: SNS allows you to publish messages to a topic, which can then be received by multiple subscribers.
    • Multiple Protocols: Supports delivery of messages to different protocols, including HTTP/S, Lambda, SQS, SMS, and email.
    • Fan-out: Allows messages to be delivered to multiple endpoints simultaneously.
  • Ideal For: Use cases where you need to broadcast messages to multiple consumers at once, such as alerting systems, mobile push notifications, and real-time updates.

AWS EventBridge

Use Case: Event Bus for Event-Driven Architectures

  • Scenario: Use EventBridge when you need to build event-driven applications with more complex event routing and filtering requirements.
  • Features:
    • Event Routing: Allows you to route events from your own applications, integrated AWS services, and third-party SaaS apps.
    • Event Filtering: Enables you to filter and route events based on event patterns and rules.
    • Schema Registry: Provides a schema registry to store event schemas and discover event structure.
    • Integrated Services: Seamlessly integrates with a wide range of AWS services and third-party SaaS providers.
  • Ideal For: Use cases requiring sophisticated event processing, routing, and integration with multiple AWS services and third-party applications, such as automated workflows, application integration, and real-time processing.

When to Use What?

  1. AWS SQS:

    • When you need a message queue to decouple components and handle asynchronous tasks.
    • Suitable for scenarios requiring guaranteed message delivery and handling large volumes of messages.
  2. AWS SNS:

    • When you need to send messages to multiple subscribers using a pub/sub model.
    • Ideal for broadcasting messages, notifications, and real-time updates to multiple endpoints.
  3. AWS EventBridge:

    • When you need advanced event routing and filtering capabilities for building event-driven architectures.
    • Suitable for integrating with multiple AWS services and third-party applications, automating workflows, and handling complex event processing.

Additional Resources

By understanding the unique capabilities and use cases of SQS, SNS, and EventBridge, you can choose the right service to optimize the performance and scalability of your applications.