Building event-driven applications at scale with Amazon EventBridge

This article describes Amazon EventBridge's relaunched Custom event bus, which simplifies event-driven applications across multiple accounts by replacing complex forwarding topologies with a single shared bus.

• Platform teams create one shared bus and control publishing/subscription access via resource policies or AWS RAM
• Application teams create self-service Subscribers in their own accounts without waiting for provisioning
• Supports Avro, Protobuf, and CloudEvents formats alongside JSON with schema registry integration
• Subscribers offer per-group FIFO ordering, event retention for historical replay, and JSONata transformations
• Direct delivery to AWS services (SQS, SNS, Lambda, Kinesis, DynamoDB) eliminates proxy functions
• Separate ingestion and delivery charges enable per-team billing and cost tracking
• Runs alongside classic Custom event buses for incremental adoption

The new design removes operational complexity by consolidating governance on one bus while enabling teams to manage their own Subscribers independently.