Definitions

An application programming interface (API) is a computing interface to a software component or a system that defines how other components or systems can use it. It defines the kinds of calls or requests that can be made, how to make them, the data formats that should be used, the conventions to follow, etc.

In networking a node is either a connection point, a redistribution point, or a communication endpoint. In general, a node has a programmed or engineered capability that enables it to recognise, process, or forward transmissions to other nodes.