When creating applications and systems for business, developers seldom want to have to start from scratch. Instead, they find that their time is more effectively used when they rely on existing infrastructure, designing their application to take advantage of proven resources that are already firmly in place. And similar to how the creator of a new home appliance will incorporate a pre-existing plug design so that it can function using common power sockets, developers rely on application programming interfaces (APIs) to “plug” their apps into existing company networks.

The API is a collection of tools, definitions, and protocols designed to assist in building and integrating new application software.