We’ve been waiting for a while for this, but the SfB Online Trusted Application API Preview is here!
My understanding is, like other Cloud preview features, it will be a staggered rollout so all abilities are not there in the preview.
The Trusted Application API is a Rest API that enables developers to build Skype for Business Online back-end communications services for the cloud. The API aims to provide developer opportunities similar to Skype for Business Server’s Unified Communications Managed API (UCMA) but for SfB Online.
The API enables a cloud-first approach and additional powerful features that aren’t available to on-premises Skype for Business Server customers through UCMA.
Key use cases include; Attendant Console, Customer engagement / Contact Centre, Recording, Compliance, Bots, Meeting Management, Click-to-chat, Click-to-call, and Value Add Solutions
As an example of new abilities this will unlock, Microsoft have released some free open-source Virtual Health Templates for Skype for Business development
Further documentation is available here: https://msdn.microsoft.com/en-us/skype/trusted-application-api/docs/overview?f=255&MSPPError=-2147217396