Organizations building event-driven applications on Amazon EventBridge typically start with a single custom event bus in one account. This works well when a single team owns the architecture. As adoption grows across the organization, though, things get complicated. AWS best practices recommend a multi-account structure, which means each team runs in its own account. To route events between them, teams create multiple event buses connected through cross-account rules or bus-to-bus configurations. This workaround reintroduces the operational complexity that serverless architectures are meant to eliminate. Platform teams lose visibility into who is subscribing to which events, cross-account and bus-to-bus routing charges compound quickly, and teams that need capabilities like event ordering are forced to build complex workarounds or adopt…
Introducing enhanced custom event buses in Amazon EventBridge for enterprise-scale event-driven applications | Amazon Web Services

