Analysis of an API: how do it really work?

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Analysis of an API: how do it really work?
Analysis of an API: how do it really work?


There was a time in which APIs were only used for developing tools for such operating systems as Windows. Few people knew about these initials which are nowadays part of the vocabulary of all developers as well as, indeed, any company offering products or services on the internet. 

Although they are usually simply defined as a mechanism for communication between different programmes, websites and applications, the insides of these technological windows are composed of codes.

Developers use programming language to express a series of rules and specifications for two softwares to communicate with each other. According to the type of norms it includes, an API can be used for an application to interact with the operating systems (such as the WinAPIs), with a database (DBMS) or with communication protocols.

On the internet, however, it is those originally known as RESTful APIs that are mainly used. The first part of its name stems from Representational State Transfer (REST), the software architectural style that rules the internet: a series of norms that all elements of the hypermedia system must meet and which mark their interactions as well as the interpretations they make of data.  

Nowadays, the meaning of REST has expanded to designate any interface between systems using the HTTP protocol for communication, data exchange or for ordering the execution of operations. And this is the procedure followed by the APIs on the Internet, which is why the term, which is often omitted, was initially added.   

Saving on time and resources

Thanks to these interfaces, the developers of a website or application can use data or functions created by another platform without any need to have to program them starting from scratch or, on the part of those lending their tools, to give details about them (although they do place restrictions on their use). This is why, in terms of computer science, they are regarded as an abstraction layer or level, a way of concealing how operations are really executed.

Thus, the APIs specify the functions of a library (the full service menu), which is left available for third parties by its owner, and give a detailed description of the routes which the external software must follow to gain access to it.

At the same time, the foreign tool is designed for making specific requests and interpreting the answers. For example, if an application wants to integrate a map from Google Maps, its developers must programme it so that it can communicate with the API of Google Maps and correctly integrate the map provided by the latter.  Among several other giants, Twitter, Facebook and Amazon offer their application programming interfaces in REST format.

Other platforms, however, use the SOAP (Simple Object Access Protocol) communications protocol, an older alternative system developed by Microsoft to permit an interaction between applications.  Its functioning, based on XML language for web services to exchange requests and answers, is simple, but applying it requires an extra effort from the developers, due to the difficulties entailed in changing the programming interfaces.

Understanding the functioning of APIs and the communication framework they involve is complex, but it is now essential to know the basics of this as it has become an everyday issue.

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