Which of the following best describes the functionality of an API?

An API, or Application Programming Interface, serves as a set of rules and protocols that allows different software applications to communicate and interact with each other. It acts as an intermediary that enables developers to access features or data from other applications, services, or platforms.

When you consider the functionality of an API in the context of connecting different devices and platforms for authentication, it highlights how APIs manage interactions and exchanges between systems. For instance, when you log into a third-party application using your Google or Facebook account, an API facilitates that authentication process by sharing necessary user information securely between the platforms.

The other options focus on functionalities that do not accurately represent the primary purpose of an API. A database management tool is specifically designed to create, manage, and manipulate databases, while compiling code into executable files pertains to programming processes, not directly related to the role of an API. Enhancing browser speed is more aligned with performance optimization techniques rather than the capabilities of an API.