An API is a set of programming instructions and standards for accessing a web-based software application. A third-party API is an interface that allows other applications to access the functionality of a separate application. This can be done either by providing access to the functionality directly, or by providing an adapter that translates the third-party API calls into calls that the separate application can understand.
The advantages of using a third party API include the ability to add new features and functionality to an existing application without having to write any code, and the ability to utilize the functionality of another application without having to worry about the underlying implementation details.
The disadvantages of using a third-party API include the potential for the provider of the API to change the API without notice, which can break the functionality of the consuming application, and the fact that the provider of the API may charge for access to the API, which can increase the cost of the consuming application.