So, or as you say, Leo, it might just be a completely dense binary protocol, which is their own API.

IAX is a binary protocol, designed to reduce overhead especially in regard to voice streams.

It uses UNIX pipes under the hood and has a relatively efficient binary protocol.

Flare protocol is a binary protocol.

Internode protocol is a binary protocol.

An interface in the UML may also be considered a binary protocol.

H.323 is defined as a binary protocol, which allows for efficient message processing in network elements.

It defines a binary protocol for controlling the properties of computer monitors from a host device such as PC, set-top box, etc.

OpenWire is a binary protocol designed for working with message-oriented middleware.

The binary protocol is opc.