What is API? Definition and application of Web API in website design

What is API?

API stands for Application Programming Interface, which is understood as application programming interface. API is a means for two or more different applications to exchange and interact with each other. In fact, the API is a tool for creating efficient and convenient human-computer interactions.

Through the API, developers can easily access and retrieve data from the server to display on their applications, software or website.

For example, you are writing a software for Windows 10 and you want your software to interact with Windows services and features. From low level like changing the wallpaper, controlling the scroll wheel, scroll bar or anything related to the GUI (user interface), to advanced like accessing system files, editing the registry or libraries. system, turn on / off services, etc. All of these can be done through the free Windows API available for Microsoft.

API has been around for a long time and has been used in many different types of applications and software. The latest generation of API, Web API, can be used in any system such as operating system, database (database), web-based system (web-based system), application library or even lice is in the computer hardware.

Development trend of API

In terms of API protection policies, there are two types: companies that protect their APIs and companies that provide APIs for free. Companies that advocate for API protection profit from registered third-party software developers, asking for their permission. The companies in this group are usually device manufacturers, especially gaming devices like Sony with their PlayStation systems.

On the contrary, the second type is companies that provide product APIs for free. Anyone can freely use these APIs to write 3rd party software, but users still need to buy software from companies to use. As a result, free API companies still make money, even free APIs bring more 3rd party software, pervasive efficiency and stronger marketing.

The biggest example in this area is ecosystems like Microsoft, Apple and Google. They free most of their APIs, in exchange developers write software for their operating systems, and users have to buy Windows or MacOS to use them. For Google, it can be said that API is what makes applications in their ecosystem increasingly popular and accessible to people around the world.

Microsoft provides the Windows API for free, so anyone can write software for this OS

Nowadays, the development trend of API is in favor of type 2, which is provided free of charge for anyone to use and earn indirect profits from those APIs. This contributes to the API is becoming more and more popular, the API runs everything on the internet and in life.

Increasing popularity, standards for API for friendliness, ease of understanding, and ease of use are also added. Not to mention, there are even Software Development Procedures for APIs with standards of design, construction and testing to ensure the creation of comprehensive and effective APIs. Security standards and technologies have been upgraded to help minimize risks or exploit security holes. All API activities are also monitored on a large scale, so the performance is getting higher and higher.

With the proliferation of mobile devices, applications and mobile services, APIs are now designed to be more suitable for mobile developers. In fact, mobile applications and web applications take advantage of more APIs than all else, creating the motivation for API growth.

According to ProgrammableWeb , one of the largest free API stores in the world, there are now over 21,000 APIs that can be freely used. The API is divided into more than 450 different categories, covering every area of ​​life.

It can be seen that API plays an extremely important role in running every system, which is the key to open the future of intelligence, synchronization and automation of people. In particular, the Web API is the latest, innovative and breakthrough technology that helps the API go deeper into our lives.

REST - RESTFul API and applications in website design

The Web API is the latest type of API design that complies with the most common API standards, along with many superior advantages over older technologies. However, before we talk about Web API and its applications in website design, we need to know about the API design standards, the most popular and most important is the REST standard.


REST, short for Representational State Transfer, is a model architecture that dictates how applications communicate and interact with each other. The basic REST architecture consists of 3 parts: an external server that stores data, an API server, and a client. The client can be anything, from web-based applications, libraries, or even different parts of a computer software, etc.

Simple operation diagram of a REST system

REST allows the client to access the API server and execute commands such as retrieving, modifying or deleting, etc. data from the external server. It is important that REST allows programmers to freely access and edit data from the server without having to know how the system works. Just by using the API, they can get the results they want regardless of whether the data server is a Linux or Windows computer or some other software.

The main protocol used by REST is HTTP. Most web services or applications (web services) today use the HTTP protocol, one of the fastest and most efficient protocols in the context of a fast network connection speed - making REST an architecture. has the fastest speed.

In addition to that convenience, REST has another advantage of using a stateless protocol, which is roughly stateless. Specifically, the REST system does not use sessions and cookies, and does not need to know that information in each request made to the external server. As a result, REST reduces the load on external servers and improves performance.

Initially, REST was designed for use in web services because web apps are increasingly popular. However, any software can use REST applications to communicate with other applications more efficiently and quickly.

Because of these reasons, REST has become the default standard for any protocol. APIs designed with a REST architecture are called RESTful APIs.

4 basic CRUD commands

CRUD (Create, Read, Update and Delete) are the four basic functions of any database system. The REST architecture and RESTful APIs fully support 4 CRUD commands, allowing you to freely manipulate data from the server as you like (if allowed).

The 4 basic CRUD commands in REST architecture have different names, respectively:

POST: create a new data, information
GET: get / read a data, information
PUT: update data, existing information
DELETE: delete data, information on the server
In particular, the GET command is the safest and most popular, allowed by most RESTful APIs today. The remaining 3 commands more or less alter the original data on the server, which can lead to unintended crashes. Only those APIs that are specifically designed and authorized, such as partner APIs or admin (admin), can execute those commands.

In short, RESTful API is the quality standard that most modern APIs must meet. It ensures important functions and improves both performance and speed in API operations.

What is the Web API?

Web API, also known as ASP.NET Web API is a framework for building and programming web services (HTTP services). It is a modern RESTful API that satisfies all the conditions of REST as well as other similar standards, optimized for web applications, online services. Owning advantages over the previous API types, the Web API has gradually gained the trust of developers and website developers.

Advantages of Web API

Easy to write and tweak, a lot easier than previous frameworks like WCF or Web service
Easy to use, creating user-friendly user experience (UX)
Meet common standards like REST and HTTP
Support for HTTP components and components (caching, versioning, HttpResponseMessage, HttpRequestMessage, ...) and MVC (controler, container, routing, ...)
High security, all requests must be validated 2-way.
Allows data to return in many popular formats like XML or JSON
Can host in many different types of clients such as web-based applications or desktop software, etc.

Application of Web API in programming and website designing

With the above advantages, Web API provides and improves the features, as well as the performance of modern websites. Instead of static pages with rigid content, websites today can use the Web API to provide more flexible and personalized content.

1. Search function

Spoonacular is an incredibly powerful, detailed recipe and food search tool

Search engines (search engine - SE) are indispensable in websites. However, if using the normal search function, users may not be able to find what they want when the amount of content is huge and complex.

In addition, on specific websites users will want to search for specific types of content.

For example, on the cooking website, probably the most searched item is the recipes, information, nutritional ingredients of the dish. Not to mention, sometimes it is necessary to add conditions such as low-fat food, good for pregnant women and children, allergy-free ingredients, and how many people for the meal, cook for a few minutes, etc.

Therefore, websites can use the popular, powerful SE API to increase the accuracy when users search. Search engines that specialize in a particular area will be useful to websites of the same topic. Finding and finding the right things will help users feel more satisfied and interested, contributing to improving the UX of the website.

2. Interact and integrate Facebook, Twitter, Zalo

Social networking platforms (MXH) today are not only encapsulated on their website, but also present on all other websites. Most websites have links or even integrate the functions of MXH.

The most typical examples are Facebook's Like and Share buttons, Twitter's Tweet button, Google+ +1 button or Zalo's Share button, etc. under each post. In addition, some sites also use the Facebook comment box for discussions under their posts. Viewers do not need to create a new account, but can use the account logged into Facebook to comment quickly and conveniently.

To do so, website designers must use Facebook, Twitter or Zalo APIs to embed their social functions into their pages. Through API, website and social networks can send / receive data back and forth easily, and viewers interact with the website as if surfing Facebook, Zalo in a normal and comfortable way.

3. Building an online sales website

The API not only improves the UX user experience, but it is also an important tool for developers' work. There are many applications of API in building website infrastructure, such as designing an online sales website based on an available platform like Shopify.

Shopify is a platform for designing online shopping stores with all necessary e-commerce (e-commerce) functions such as shopping carts, electronic payment, price updates, etc. Just use the API Shopify's buttons, components, and websites will have the typical e-commerce website functions. The construction process will be shortened and ensure the necessary features for the online store to operate effectively.


Through this article, I hope you have grasped what API is relative, the values ​​and applications of Web API in website design as well as in our lives. From being a protocol that enables applications to interact with each other, the API is expanded and improved to operate every software and hardware device, present everywhere online and offline.

Compared to example 3 above, if it is not an online sales website, the use of APIs also helps to reduce the workload and improve accuracy in the process of designing other types of websites. They help programmers - builders of the future - complete works faster and more solidly; It also helps users to enjoy the experience more convenient and wonderful.

The API, especially the Web API, has been and is the universal key to a convenient, complete and modern life.

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