What API means? Is it something to do with programming? Can it be helpful for users ?
An API (Application Programming Interface) is a program that allows one application to interact with another. Simply an API is a messenger that takes requests and tells the system what to do, then returns the system’s response back to you. The API can be used, for example, to track an investment portfolio, or to trade directly on the markets. Trading API allows you to interact with the trading system. More precisely, it allows you to make trades directly on the exchange. This is especially useful for traders who run algorithmic models in their own trading systems and want to receive live quotes and be able to execute trades manually or automatically. API trading is especially popular with large hedge funds and trading companies due to their use of algorithmic trading programs, but even private investors can use trading APIs provided by online brokers and recently cryptocurrency exchanges. Most of the leading crypto asset exchanges such as Binance, Bitfinex, Bittrex and Coinbase Pro offer trading APIs to their clients. These APIs allow you to submit live prices as well as directly execute the order.
To illustrate the problem in the best possible way, imagine that we are in a restaurant. We sit at the table and have a menu in front of us from which we can choose our favorite dish - Lasange, tomato soup or spaghetti pasta. In this particular example, the kitchen represents the system that prepares our orders. However, the key element is missing, because the kitchen will not know what we want to order. So here comes the waiter, that is our API, which passes the order to the kitchen and finally delivers it straight to the table.
And now, let's translate it into the real world. We probably booked a flight more than once. Just like in a restaurant, we have a lot of options to choose from - in case of airlines, e.g. departure airport, destination, date of departure, date of arrival, destination airport and other variables.
When you click "search for flights", you interact with the airline's website to connect to their database. As a result, we get available flights to the location that interests us. On the basis of the given variables, we also receive a flight valuation.
What happens when we use the super search engine like skyscanner e website, which has no access to the airline's database?
Such a search engine does not connect with the airlines' data base because there is no access to it, the search engine interacts with the API of individual airlines, searches all the results and, just like our waiter in a restaurant, delivers them to us to find the cheapest and most comfortable flight among all the offers available on the market.
As you can see, we use the API in practically every activity we do while being online. Thanks to API we are able to quickly and easily reach the information we are interested in - it is the main link that allows us to combine data and our devices into an application and create one big network of connections.
API - Application Programming Interface - Allows the application to communicate with each other (e.g. your program with the operating system). It is defined on the source code level (e.g. library for a given programming language). The API's task is to provide appropriate specifications of subroutines (e.g. functions in the library), data structures (e.g. what a given array contains), object classes (define an object in programming j.) and required communication protocols (e.g. http).
For peasant's sake we can say that API allows you to use functionalities provided by another application in your application. An example is the Windows API, which allows you to create applications that take advantage of the capabilities that Windows offers (e.g. in C++ you can open a window using the function defined by the API). When you've been playing games the name DirectX or OpenGL has probably bumped into your ears. These are libraries that allow you to create 2D and 3D applications in programming languages, and they already communicate with your graphics card as standard. This is a great convenience, because APIs like DirectX and OpenGL allow you to write programs for different graphics cards in the same way (manufacturers need to adapt).
API is often used in web applications. A simple example can be downloading tweets from twitter using Twitter API. In your program, you write an HTTP query to the appropriate address and receive the desired tweets from that person.
The API is generally great because it allows you to unify problem solving so that communities can emerge that will improve the circle that has already been created and help others who want to understand how the circle works.