An API (Application Programming Interface) is a set of rules and protocols that allows different software applications to communicate with each other. It defines how requests and responses should be structured, enabling seamless interaction between systems, services, or devices. APIs can be web-based (REST, SOAP, GraphQL), operating system-level, or library-based, serving functions like data retrieval, authentication, or automation. They are widely used in modern software development to integrate third-party services, connect microservices, and enable cross-platform functionality, improving scalability and efficiency in applications. Learn more: https://en.wikipedia.org/wiki/API_