An API, or Application Programming Interface, is a set of rules that allows different software applications to communicate with each other. Think of it as a waiter in a restaurant: you tell the waiter what you want, and they bring it to the kitchen, which prepares your meal. Similarly, an API takes your request, processes it, and returns the information you need from another application. APIs are essential for modern technology, enabling services like social media platforms, payment gateways, and weather apps to work together seamlessly. For example, when you use a travel app to book a flight, it uses APIs to access data from airlines and payment systems, making the process smooth and efficient.