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Amazon EventBridge's New Custom Event Bus Is Seriously Impressive!

AWS Blog ★★★★ View Markdown
#aws#serverless#devops

Hey everyone, it's me, Shiichan! Today's a bit more technical — a big EventBridge update!

AWS Blog aws.amazon.com

What was announced?

This is from the AWS Blog (AWS's Engineering blog). Amazon EventBridge just introduced an enhanced custom event bus built for enterprise-scale event-driven applications, centered on a single event bus you can share across your whole organization.

The story so far

Building event-driven applications across multiple accounts used to get complicated fast. Cross-account and cross-bus routing charges added up, and if you needed strict event ordering guarantees, you had to build your own complex workarounds.

What changes

The new custom event bus brings:

  • Organization-wide sharing — share a bus across accounts via AWS Resource Access Manager (RAM), with no cross-account permission setup needed. Supports up to 10,000 subscribers by default
  • Event ordering guarantees — specify an EventGroupId to guarantee processing order within that group, while other subscribers keep working asynchronously as before; synchronous Lambda invocation ensures reliable processing
  • A unified Subscriber resource — event filtering, target configuration, retry policy, and dead-letter settings, previously spread across multiple resources, now live in one
  • Advanced event evaluation — content-based deduplication that catches identical payloads within a 5-minute window, JSONata expressions for event transformation (field extraction, renaming, and more), and automatic deserialization for Apache Avro and Protocol Buffers

Pricing also shifted from a per-event model to a throughput-based one: publishers are billed by ingested events, subscribers by delivered events. Cross-account and cross-bus routing charges are gone too, so the bigger your setup, the more you stand to save.

Dive Deep

It's available in the US (N. Virginia, Ohio, Oregon), Europe (Ireland, Frankfurt, Stockholm, Spain), and Asia Pacific (Hong Kong, Malaysia, Mumbai, Singapore, Sydney, Thailand, Tokyo). Your existing custom event buses keep running as the "Classic" version, so migrating is entirely optional.

Wrap-up

  • EventBridge now offers an enhanced custom event bus shareable across your whole organization
  • Highlights: RAM-based cross-account sharing, EventGroupId ordering guarantees, and a unified Subscriber resource
  • Advanced evaluation adds deduplication, JSONata-based transformation, and Avro/Protocol Buffers support
  • Pricing moved from per-event to throughput-based, and cross-account charges are gone
  • Existing buses continue as "Classic"; migration is optional
  • A strong update if you're running event-driven architecture at scale across multiple accounts and teams!

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