What is API (Application Programming Interface)?

API (Application Programming Interface) is a communication interface between software components. One of the main functions is to represent a method for achieving abstraction in programming, as well as providing a number of commonly used functions.

What is API (Application Programming Interface)?

What is API in Programming?

The API is a set of functions and procedures that a particular library offers for use by other software as an abstraction layer. They are often used in libraries.


A programming interface represents a communication interface between software components.

It is a set of calls to specific libraries that offer access to certain services from processes and often represent a method for obtaining abstraction in programming between the lower and upper levels or layers of the software.

One of the main purposes of an API is to provide a set of commonly used functions, for example, to draw windows or icons.

In this way, programmers avoid using it to program everything from scratch using their functions.

APIs are abstract software that allows it to be called the implementation of a particular API.

For example, Hello World print functions at different levels of abstraction on the screen;

  1. Doing a Job from the Beginning: On graph paper, the letter “H, e, l, l, o, W, o, r, l, d” forms a matrix of black and white squares, similar to the letter order, and using the assembly instructions, the array writes its information to the screen buffer. Using the correct instruction, it allows the graphics card to display this information on the screen.
  2. Using the Operating System to Do Part of the Job: A font provided by the operating system is installed, using this font to enable the operating system to write the text “Hello World”.
  3. Using an Application to Do Most of the Work: An HTML document with the words “Hello World” is created so that a Web browser such as Google Chrome, Mozilla Firefox, Opera, or Internet Explorer can display it on the monitor.

As you can see, the first option requires more steps, each of which is much more complex than the next option steps.

Also, it is impractical to use the first approach to represent large amounts of information, such as an encyclopedic article on the screen, while the second approach simplifies the task and requires a third way to eliminate one step and make the rest easier.

However, high-level APIs often lose flexibility; For example, it is more difficult to rotate the text around a point with a flickering frame in a web browser than to program it at a low level.

When choosing an application interface, a certain balance must be struck between its strength, simplicity, and loss of flexibility.

Applications for Sending Data

   Remote Procedure Calls (RPCs)

With RPCs, programs can communicate through procedures running on shared information buffers.

   Standard Query Language (SQL)

It is a procedural data access language that allows data exchange between applications and accesses common databases.

   File Transfer

It enables data exchange by sending formatted files between applications.

   Sending Message

It enables data exchange through direct programmatic communication through small messages formatted between paired applications.

Programming Interfaces

We can give an example the Microsoft WMI, Microsoft Win32, Microsoft Framework .NET, OpenGL, Java EE, API for SCSI, Carbon APIs for Macintosh Operating System, Common Object Request Agent Architecture (CORBA), Symfony and Drupal for programming interfaces.

Network Access Interfaces

They can be developed for any platform and operating system, or for all these systems simultaneously.

They have also been evolving as a way to access web services for several years. In this sense, the best known APIs are; Google Search is Flickr, Amazon, Google Maps.

Benefits of Using API

A good API makes it easy to develop the program because it must provide all the blocks to build it. The programmer only combines all the blocks.

The API is specially designed for programmers, as it guarantees that all programs using the API will have similar interfaces.

This also makes it easier for the user to learn the logic of new programs.

When a request is made, the server offers the advantage of having more services by calling the API.

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