An API (Application Programming Interface), is a set of rules and protocols that allows different software applications to communicate with each other. An API defines the way that different software components should interact and allows those components to be combined to create new functionalities.
API calls are the requests that an application makes to an API to access its functionality.
When a developer wants to use the functionality of an API, they make an API call to the API endpoint. The API endpoint is the URL of the API to which the developer sends the request. The API call includes information such as the request method (e.g. GET, POST, PUT, DELETE), the data to be sent to the API, and any authentication information that may be required.
There are different types of API calls. For example:
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GET: this type of API call is used to retrieve information from the API. For example, a GET request to an API that provides weather information might return the current temperature and forecast for a specific location.
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POST: this type of API call is used to send information to the API to be processed. For example, a POST request to an API that allows users to create new accounts might include the user’s name and email address as data to be processed by the API.
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PUT: this type of API call is used to update an existing resource in the API.
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DELETE: this type of API call is used to delete an existing resource in the API.
APIs are commonly used in web development, mobile app development, and IoT to connect different systems and share data and functionality. APIs are also widely used in the context of microservices, where a complex application is broken down into smaller, independent services that communicate with each other through APIs. API calls are made using various languages and libraries such as REST, SOAP, GraphQL, and gRPC. These are some of the popular libraries and languages that are used to make API calls.