API, which is short for Application Programming Interface, is the name given to the codes used by different systems to facilitate interaction between each other or to develop software.

The API defines the correct way for a programmer to write a program that requests a service from another application. To give an example, if you are going to pull data from another program, you send the information requested by the API of that program and it will send you the information you want in return. This is how the API tells you what to do. APIs are implemented with function calls made up of verbs and nouns and usually do not contain an "Interface", even in its abbreviation. So there is no user screen.

Importance of API

The main reason for the existence of APIs was that while the software was operating in their own eco systems at first, with the development of technology over time, the communication of applications with each other, that is, the spread of data exchange. A very important part of this is commercial activities. For this reason, many commercial institutions issue their own APIs and provide services to their customers through different channels.

Let's explain with an example. You can access Youtube from your web browser, from your mobile device, or from your television. The operating system on your computer can be Windows, the operating system on your mobile phone can be Android, and the operating system on your television can be WebOS. These separate operating systems have their own rules. In order to bring the information in Youtube videos, instead of coding in a way that each operating system will accept separately, an API that brings information in a format that will be accepted by all is made and made available to them. Thus, a single API provides data exchange with all of them. In other words, Youtube applications working in different environments exchange data from a single channel with the API.

Today, the basic data exchange of APIs is done via the internet. Many large companies use APIs to offer their services to their customers. Especially e-commerce companies, social media platforms or search engines use APIs most widely. The best example of this is Google maps, which are on many websites and show their location for communication. The person who made the site uses Google's API to make the map appear on the site. For this, it is sufficient to place the code specified by Google on the site. The API takes care of the rest. In addition, we see that some websites show their posts on their social media accounts (for example, the last tweets) on the site. This happens again thanks to APIs.

APIs have improved software quality in recent years. The increasing use of APIs in cloud solutions, the API of mobile applications and internet of things (iot) devices Data exchange with these devices increases the functionality of these devices. In the past, the concept of shopping on the internet was seen as a business done only from computers, but today, more than half of the orders given or the desired service is made from mobile devices.