An API call, or API request, is the process of a client application submitting a request to an API and that API retrieving the requested data from the external application or server. In other words, an API call allows one application to request data or services from another application. An API call is initiated by a client application, which sends a request to the API, and the API responds with the requested data.
API calls require a unique identifier to authenticate the calls to the API, which is an API key or access token. These identifiers are used to grant or deny requests based on the clients access permissions and track the number of requests made for usage and billing purposes.
API testing involves making API calls to different endpoints, getting responses, and validating the status codes, response times, and data in those responses. API calls can be used for a variety of purposes, such as allowing software programs to communicate with each other, accessing data from another program, or instructing an application or server to perform a specific operation.
API calls can be private and have a specific and limited set of users or be a public API available for anyone to use. API calls are considered safe if they are made with the correct credentials and not being used for malicious purposes. However, API calls can lead to an attack if they are not properly secured, as they are made from a different domain than the one that is being called from.
