What is API , Types of APIs and there features and Testing tools What is API: An API, or Application Programming Interface, is a set of rules and protocols that allow different software programs to communicate with each other. APIs specify how software components should interact, and allow for different systems to be connected in a way that allows them to share data and functionality. This enables developers to create new applications and services by building on top of existing systems, rather than having to start from scratch. Types of APIs: There are several types of APIs, including: Open APIs , also known as external or public APIs, are available to developers and other users with minimal restrictions. They may require registration or an API key, but they can be accessed easily and used to connect to a wide variety of external systems. Internal or Private APIs are those which are hidden, behind a firewall and are not intended for external use. They are used within the c