APIs (Application Programming Interfaces) are sets of rules and protocols that allow different software applications to communicate and interact with each other. They define the methods and data formats that developers can use to access the functionality of a software component, service, or platform, enabling seamless integration and interoperability between different systems. APIs facilitate the exchange of data and services across diverse platforms and devices, allowing developers to leverage existing functionality and build upon it to create new applications. They are fundamental building blocks of modern software development, enabling the creation of complex and interconnected digital ecosystems.