Software design where components communicate through events rather than direct calls. Like a newspaper where different departments react to breaking news independently.
When a customer places an order, it triggers events for inventory, shipping, and billing systems simultaneously.
These services provide managed event routing (publish/subscribe) so producers emit events and multiple consumers react asynchronously. They commonly integrate with serverless compute (AWS Lambda, Azure Functions, Cloud Run/Functions, OCI Functions) and messaging services for buffering or streaming when needed.