Every relationship between people is based on some specific agreement. In other words — a deal is a universal basis for any kind of communication. Participants in such deals do not have to be living organisms; they can also be artificial programs.
From this idea comes API — one of the essentials of the IT world. You may hear of it in development cases or while looking through tester vacancies. APIs can help to make crypto exchanges just like blockchain and big data does. So, what is it, and what role does it play in the modern world? Let’s find out!’
Definition
API is an acronym for Application Programming Interface. In these terms, the elements have the following meaning:
- Application — any type of software that has a function or a set of functions;
- Programming — this refers to the main participants in the interactions (programs);
- Interface — this defines the core aspects of the interaction between two or more subjects.
Simply put, an API is a set of elements that help one program to use another. We all face this from time to time. For example, when looking at what the weather is like on a regular basis, for instance, every 2 minutes. Then a mobile application connects to it through an API to show you the temperature and update information when needed.
When creating a complex piece of software or a program, developers use an API to create rules between different elements. They set specific information about a program which includes:
- Operation;
- Input Data;
- Output Data;
An API answers one question: how can programs contact each other? With this set of algorithms, the programs know what they can give and take from each other.
APIs can be created on every level of functionality. For example, there could be one API for system inclusion and another for providing reports.
Architectural Types of APIs
To define API, experts often use ‘client’ and ‘server’ terms. The first is an application that sends a request, and the second is the one receiving it. Like in the example mentioned earlier, a mobile weather app is a client, and the weather forecaster is a server.
There are several types of APIs:
RPC API — this operates as a ‘request-response’ function. The client sends requests, and the server responds to them with a specific result;
SOAP API — the meaning of this type is ‘Simple Object Access Protocol.’ This is one of the first APIs ever created. This protocol ensures messaging between participants via XML (eXtensible Markup Language);
Websocket API — this is a recent design of a web API. It uses a JSON object to transfer data between the client and the server. In this case, the server can make return calls to connected clients;
REST API — means ‘Representational State Transfer.’ This is one of the most popular and flexible APIs on the market. The client sends a request, and the server uses this input to launch an internal function and provide necessary data. The main aspect of this API type is that no client information is saved within the servers. It is much like typing a URL address — you do this all the time, right from the beginning;
Web API — this is a type used only for web applications and servers. APIs were created long before the Internet, so it is common to use similar interpretations.
Types of APIs Based on Application Functions
There is also another classification of APIs based on the sphere of usage:
- Private IPS — for internal operations in business and development;
- Public IPS — can be used by anyone, often requires authorization or other types of access;
- Affiliate IPS — used for partnership between industries;
- Integral IPS — a selection of two or more APIs for complex requests.
API Documentation, Usage, and Specifics
API can be created automatically via specific instruments or manually by a professional developer. They are often written in simple language and include examples and any possible problems that could appear in the process.
After creating this program, you should install it as an API HTTP client. With that, you can easily customize and manipulate your documentation at any moment. If you do not possess an API client, you can structure your request in a browser.
There are also automatization programs that are used by big companies called API Gateways. These allow users to perform user authentication and gather statistics.
Another useful tool is called GraphQL. It enables you to make many different requests to various servers and get data quickly and smoothly. Many application developers use this tool.
Many IT companies are looking for testers who can make SOAP and REST services and find some issues in the documentation. So be sure to study API if you are interested in the subject!
Conclusion
APIs are an essential yet unnoticed feature in the modern world. Some experts don’t even know about them and refer to these functions using many different terms. Be sure to study API basics to upgrade your IT knowledge and keep looking for helpful new inventions!
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