Definition: Serverless event bus that connects applications using data from your own services, SaaS applications, and AWS services.
— Source: NERVICO, Product Development Consultancy
What is Amazon EventBridge
Amazon EventBridge is a serverless event bus that facilitates connecting applications through events. Unlike SNS or SQS, EventBridge allows defining sophisticated routing rules based on event content, filtering by complex patterns, and connecting with over 20 AWS services as direct targets. EventBridge can also receive events from external SaaS applications like Zendesk, Datadog, or Shopify, making it a central hub for event orchestration in modern architectures.
How It Works
Events arrive at the EventBridge bus from three sources: AWS services (changes in EC2, S3, etc.), custom applications publishing custom events, and integrated SaaS applications. Each event is a JSON document with a standardized structure that includes source, type, timestamp, and detail. EventBridge rules evaluate each event against defined patterns and route matching events to one or more targets: Lambda functions, SQS queues, Step Functions state machines, HTTP APIs, or event buses in other AWS accounts. EventBridge also offers an event archive that allows storing and replaying past events for debugging or recovery.
Why It Matters
Event-driven architectures need a reliable mechanism to route events between services in a decoupled manner. EventBridge surpasses the limitations of SNS by offering content-based filtering, native integrations with AWS services, and the ability to receive third-party events without custom code. For teams building complex distributed systems, EventBridge significantly reduces integration code and provides a centralized observability point over the entire system’s event flow.
Practical Example
A subscription company configures EventBridge as its central event bus. When a user cancels their subscription, the billing service publishes a “subscription.cancelled” event. An EventBridge rule routes this event to three targets simultaneously: a Lambda function that updates the CRM, an SQS queue that feeds the email retention flow, and a Step Function that processes the refund. Months later, the analytics team needs access to these historical events and uses the EventBridge archive to replay them into their data warehouse without modifying any existing service.