API stands for Application Programming Interface. To understand the actual role of the API, let’s look at a simple analogy: you are hungry, so go to a hotel to enjoy a good meal, but go to a restaurant to sit there is not for your purpose. You must order food through an assistant (or waiter). Here we can say that the server is an API. The hotel is a hub that provides all kinds of food, but the assistant will take care of your needs and provide you with the quantity/type of food you need. It is not the database or even the server, it is the code that governs the access point(s) for the server.
It provides you or your application with the required information. There are many practical examples. For example, there is an openweathermap.org website that provides you with weather conditions in different locations and formats. In other words, users can select specific links to display information in the desired way (in units of measurement or city or country/region code, etc.).
For each API used in the application, the API key that will be used in the application must first be generated. This allows the service provider to track your request (depending on the plan used, the number of visits per day may be limited). Similarly, many travel websites use APIs from various airlines, hotels, etc., to provide users with information about availability, room availability, location, business hours, etc.
Even Google Maps has API, and you can use it for any purpose in your application. The process remains the same: first, generate the key, and then use the API accordingly by checking the documentation. This is a very basic understanding of API, in reality, it is a vast subject, and accordingly, Mobifly will bring more knowledge for the same in other blogs.