API

     API is an acronym that stands for Application-Programming-Interface.

     An Application-Programming-Interface can be thought of as a set of routines, protocols, and tools for building software applications. APIs specify how software components should interact, such as what data to use and what actions should be taken.

     API’s are so very useful for their abilities of extrapolation, aggregation, and organization of very specific data.

As an example, we can take the Coinmarketcap API.

Using the API provided by CMC we can build our own listing service or use their data points for the creation of charts & other financial instruments. However, their API will not help somebody build an encyclopedia.