AsyncAPI is an open specification meant to be an industry standard for defining asynchronous APIs. It helps unify documentation automation and code generation and manages, testing, and monitoring asynchronous APIs. The specification provides a language for describing event-driven systems' interface regardless of the underlying technology and supports event-driven architecture's complete development cycle.
In March 2021, eBay launched the first AsyncAPI-based contracts for the new business event notification capabilities.
Aside from the usual considerations of scale, delivery guarantees, monitoring, playback and recovery, the new platform was also designed for data security; Elliptic Curve Cryptography- based message integrity verification; and support for multiple protocols and payload schema versions. Some of the advanced features also include multi-tenancy with isolation guarantees between different “tenants” of this system, as well as internally separating use-case-specific concerns from core platform concerns.
When it came to exposing the event streams of this new platform as a contract to eBay’s external developer community, the Async API 2.0 Specification was the unanimous choice. They found AsyncAPI extremely helpful because of the ease of use that results from the delineation of channels, protocols and bindings; separation of concerns between publish and subscribe; and separation of protocol-specific and application-specific headers.