A Web API (Application Programming Interface) is a set of rules that allows different software applications to communicate over the internet. It enables developers to access specific features or data from a web service, making it easier to integrate various applications. For example, a weather application can use a Web API to retrieve current weather data from a remote server. Web APIs typically use standard protocols like HTTP and data formats such as JSON or XML for data exchange. They are essential for building modern web applications, allowing services like social media platforms, payment gateways, and cloud storage to interact seamlessly with other software.