Unless BAPS3 is implemented as a single monolithic entity, its services need to communicate with each other to fulfil the tasks of a playout suite. We specify two interfaces for inter-service communication:
The internal API, which is a lightweight, line-orientated textual API used for communication between server-side services;
The external API, which is a HTTP-based JSON API used for communication specifically between the platform and client services.
We consciously chose not to use the existing BAPS2 API, for the following reasons:
The BAPS2 API is based on a binary protocol that is difficult to debug, and provides a lack of transparency that outweighs the performance advantages of using the binary protocol;
The HTTP-based external API allows Web-based implementations of the client service, amongst other flexibility benefits;
The change from BAPS2 to BAPS3 allowed us to correct some oddities and counter-intuitive design decisions in the BAPS2 API.
We define both APIs in turn, starting with the internal API and following with the external API. For each API, the protocols underlying the API are first described, followed by a detailed reference of the requests and responses used in that API.
For the internal API, requests and responses are grouped by feature flags, which are used by the API to describe the feature set of an internal API server.