EventBridge
EventBridge is a serverless event bus that routes events from AWS services, custom applications, and SaaS providers to targets based on content-based filtering rules. It's the successor to CloudWatch Events.
EventBridge is a smart postal sorting office — packages (events) come in from any sender (AWS services, your apps, SaaS), are sorted by content (rules), and delivered to the right address (targets). The DLQ is the undeliverable package bin.
Event buses: default bus (AWS service events), custom buses (your app events), partner buses (SaaS like Shopify, Stripe). Rules filter events using pattern matching on any event field. Targets: Lambda, SQS, SNS, Step Functions, Kinesis, API Gateway, EC2, ECS tasks, and more. EventBridge Scheduler replaces CloudWatch Events scheduled rules with finer-grained scheduling (one-time and recurring). EventBridge Pipes: point-to-point integration between sources (SQS, DynamoDB Streams, Kinesis) and targets with optional filtering and enrichment.
EventBridge has a default limit of 300 rules per bus. Content-based filtering can match on event source, detail type, and any field in the detail JSON using patterns (prefix, suffix, numeric ranges, anything-but). EventBridge Archives capture all events for replay — critical for debugging and event sourcing patterns. Schema Registry automatically discovers event schemas and generates code bindings. EventBridge's archive and replay capability enables temporal decoupling: replay events from days ago through new Lambda versions during incident response or feature deployment. Dead-letter queues on targets handle failed deliveries.
EventBridge is my go-to for event-driven architectures. I use the default bus for AWS service events (EC2 state changes, S3 events, RDS snapshots) and custom buses for domain events between microservices. Content-based routing rules eliminate conditional logic in consumers. EventBridge Archives make replay possible for debugging or re-processing. Pipes simplify point-to-point event flows without custom glue code.
Using EventBridge when you need guaranteed delivery or queuing. EventBridge is fire-and-forget — if a target is unavailable, you need a DLQ on the rule. For guaranteed at-least-once delivery with retry, SQS is more appropriate.