Events are common mechanisms in event-driven architecture or serverless applications. However, producers or cloud providers tend to support them in different forms, which prevents interoperability across platforms and infrastructures. CloudEvents is a specification for describing event data in common formats to provide interoperability across services, platforms and systems. It provides SDKs in multiple languages so you can embed the spec into your application or toolchain. Our teams use it not only for cross-cloud platform purposes but also for domain event specification, among other scenarios. CloudEvents is hosted by the Cloud Native Computing Foundation (CNCF) and now runs as an incubator project that has been gaining increasing industry attention.
Outside the function code itself, applications written as serverless functions are tightly coupled to the cloud platform on which they're hosted. Although events are a common FaaS-triggering mechanism, and every cloud provider supports them in some form, the current proprietary specifications prevent interoperability across clouds. The CloudEvents specification is a burgeoning standard that has been accepted into the CNCF Sandbox. The standard is still in active development but several language bindings exist and Microsoft has announced first-class support in Azure. We're hoping other cloud providers will follow suit.