An API (Application Programming Interface) is a set of protocols, routines, and tools for building software and applications. It specifies how software components should interact and APIs allow for communication between different systems and applications.
APIs provide a way for different software systems to communicate with each other and exchange data in a standard format. For example, an API could allow a weather website to access current weather data from a weather service provider, or enable a mobile app to access a user's social media profile information.
APIs can be created for internal or external use, with different levels of access and security. They can be RESTful, meaning they use HTTP requests to GET, PUT, POST, and DELETE data, or they can use other protocols such as Simple Object Access Protocol (SOAP).
In short, APIs act as a mediator between different software systems, enabling them to communicate and exchange information with each other in a standardized way.