API stands for Application Programming Interface. An API is a standardized way to allow two software systems to communicate with each other. Usually, one of the systems provides an API that is "consumed," or used, by the other system.
It works like this: A software/system like Voxy provides an API, which consists of a series of pre-made URLs, or endpoints, that are ready to accept requests from the “consumer” and either perform tasks or exchange data. These URLs are not accessed through the browser. Instead, they are accessed by something called an HTTP request that activates the URL and requests a response from the API.
Example: The Voxy Partner API has the following endpoint: https://partner-api.voxy.com/partners/users/. If the partner makes an HTTP request to that endpoint, it will return a data object that contains a list of all the users users from the organization.