EventBridge: Event Bus and Rules
Publish events to a custom EventBridge bus, write event pattern rules to filter and route events to Lambda, SQS, or Step Functions targets.
What Is Amazon EventBridge?
Amazon EventBridge (formerly CloudWatch Events) is a serverless event bus that makes it easy to connect applications using events from AWS services, your own applications, and SaaS providers. Events are JSON objects; EventBridge routes them to one or more targets based on event pattern rules. Unlike SQS (point-to-point), EventBridge is a pub/sub routing layer — one event can fan out to many targets simultaneously.
Event Buses: Default, Custom, and Partner
EventBridge has three types of event buses. The Default bus receives events from AWS services (EC2 state changes, S3 events, CloudTrail API calls, etc.). Custom buses are buses you create for your own application events — they isolate your application events from AWS service events. Partner buses receive events directly from SaaS providers (Zendesk, Datadog, GitHub, Shopify) through pre-built integrations, without needing a polling Lambda.
# Create a custom event bus for your application
aws events create-event-bus --name my-app-bus
# Put a custom event onto the bus
aws events put-events --entries '[{
"Source": "com.myapp.orders",
"DetailType": "OrderPlaced",
"Detail": "{\"orderId\": \"ORD-123\", \"total\": 99.99}",
"EventBusName": "my-app-bus"
}]'