WHAT IS AN API? (APPLICATION PROGRAMMING INTERFACE)

INTRODUCTION

You might have read tech blogs or magazines and probably come across the abbreviation API (Application Programming Interface). This may sound solid to you, but what does API mean and why should you think about it? Let’s begin with an uncomplicated example of human communication. They convey their needs, and thoughts along with ideas through spoken or written language, facial expressions, or gestures. Interacting with computers, websites, and applications needs user interface components such as a keyboard, mouse, and screen with a menu alongside graphical elements. Moreover, the software never requires a graphical user interface to communicate with each other. They communicate and share the data and functionalities through machine-readable interfaces known as API

Definition of API

The Application Programming Interface is also abbreviated as API which is known as the software-to-software interface that allows communication or sharing of data between two applications. Connecting your software to API enables you to expand the package of your software and offerings in a more time along with cost-effective manner. There are two components available in Application Programming Interfaces (API) and are as follows:

• Technical specifications delineate the exchange of data options between solutions with the specifications already executed in form of a request for processing along with protocols of data delivery.
• The program interface is written to the specification that represents it.

The program or software in need of information /functionality access from another program requests its API while specifying the requirements of how functionality/data must be provided. The program then returns the requested functionality/data to the former application. The API specifies the interface by which these two software or application communicate. Each Application programming interface is implemented by functional calls. This is the statement of the language that has the mandate to request the software to execute a specific service or action. Function calls are known to be phrases that are composed of nouns and verbs such as;

• Begin or end a session
• Single room type gets amenities
• Server objects restore or retrieve

Application programming interfaces serve many purposes. In general, APIs can make the development of the software simple or speed up. Functionality can be added by the developers from other providers to existing solutions or create unexampled applications utilizing services provided by third-party providers. The specialist in all these cases does not need to work on codes attempting to empathize with how the other solution works. Simply, they link up their software to another one. Just to reiterate, the application program interface act as an abstraction layer between two systems, masking the complexity along with the working details of the latter.

TYPES OF API

Understanding that not every software integration is the same is key. Therefore, all APIs are not the same. APIs are found in different categories based on different functions, access levels, and protocols. For your company’s APIs to have the desired output, it’s very crucial to make the right API type choice. For instance, an application programming interface that shares information with the public will probably have different requirements than one meant only for internal use by your employees. So to share data efficiently and safely in your company, here are the different types of APIs to choose from. These APIs are known as Web APIs. They are accessed by habitually using HTTP, or Hypertext Transfer Protocol. These are the same protocols utilized for displaying and fetching pages of the web in browsers.

OPEN APIs

Also referred to as public APIs or External APIs. These APIs are always available to be put to use by any developer. As a result, external APIs are low in measures of authentication and authorization, and the assets they share are frequently restricted. Though some application programming interfaces are free, others to use require a fee for subscription. This is based on the sum of calls made to the API. Making an API public comes with an advantage. One of the biggest abilities is sharing the data openly. This promotes external enterprises or developers to integrate with the application that has an API which makes API and third-party more valuable. As a result of restrictions deficiency along with easy implementation permitted by the open API, third parties can leverage quickly the data it provides.

For instance, Waze is a traffic application that habituates APIs issued by Municipalities along with other partners about road accidents, closures, service vehicles, and construction delays. Successfully, Waze activates easier city navigation which attracts more visitors alongside pleasing residents.

PARTNER APIs 

These APIs are externally shared only among those having commercial enterprises’ relationships with API-providing companies. The clients with official licenses have limited access thus having stronger security measures with partner APIs than public APIs. Some businesses opt for Partner APIs because they need extreme control of the resources access and as well manage how they are used. For instance, Pinterest embraced a submission-based approach to issuing access to unexampled information services via its API. 

INTERNAL APIs

Contrary to open along with partner APIs, internal APIs are intended not to be put into use by third parties. These APIs are also known as private APIs and are meant only to habituate inside the company. This type of API is used to streamline the transfer of data between systems and teams. The company’s employed developers can use these APIs but developers from external can’t. These APIs are completely kept away from the public as they are not publicly released software development kits documented. Nevertheless, dozens of the company go public with their internal APIs. It’s more efficient, traceable, and secure to make use of APIs for the internal transfer of data. Moreover, it’s also a solution that is scalable.

COMPOSITE APIs

These APIs merge multiple APIs giving developers allowance to bundle requests or calls and receive a single amalgamated response from dissimilar servers. When you require information from dissimilar data resources or applications, you would make use of composite APIs. In lieu, you can habituate this type of API to activate an automatic chain of responses and calls without your intervention requirement. As a result of a minimized number of total API calls, this type of API can course less server load along with overall faster systems, along with minimized system complexity. Commonly, they are microservices deployed in which a single job may need data from heaps of internal APIs to complete. For instance, if you decide to place an order within a shopping cart API, you may think that will take just a single request. But that is not the case because several requests here have to be executed. First, you will create a profile for a customer. Then, you will also create an order, add an item, add another and as well change the order status. In this case, with composite APIs, you can just make a single API call instead of making five API calls in a succession.

API SPECIFICATIONS 

It is the goal of API specifications to standardize the exchange of data amongst services of the web. A diverse system’s ability to write in dissimilar programming languages or use different technologies or run on different operating systems to communicate with each other is known as standardization. 

Remote procedure call

A remote procedure call is an acronym for RPC. Web application programming interfaces may comply with principles of exchange based on the procedure of remote calls. This protocol defines the interaction between client-server-based applications. A single client or program requests functionality or data from another program or server on a network located in a different location, then the server sends back the necessary response. Subroutine or function calls are other names for RPC and below are ways you can implement the remote procedure.

SOAP

Also known as service object protocol, it is used for structured information exchange in a distributed, decentralized environment, according to the Microsoft definition that created it. In general, these specifications possess some syntax rules for response and request messages sent by applications on the web. Application programming interfaces that adhere to SOAP principles activate XML messaging between systems through HTTP or SMTP for mail transfer. XML is an uncomplicated, flexible text format that is extensively used for the storage of data and its exchange over other networks or the internet. It delineates a set of rules for documents encoded in a simple format that humans and machines can read. The mark-up language is known to be a collection of symbols that can be placed in the text to define along with the labeling of parts of text documents. Extensive Mark-up Language text documents have tags that are self-descriptive of data objects, which makes the readability easy. Service object protocols are mostly used in web-based enterprise software for a high-security guarantee of transmitted data. These APIs are most preferred by payment gateway providers, CRM solutions, financial and telecommunication services as well as identity management. 

REPRESENTATION STATE TRANSFER

Representation state transfer is also abbreviated as REST, and it was introduced by well-known computer scientist Roy Fielding in 2000 in a dissertation. REST is an architectural style of software containing six constraints for application constructions that exercise over HTTP, often web services, unlike SOAP, which is a protocol. The most commonly known application of this architectural style is the World Wide Web.  A simpler alternative for REST is known as SOAP, which dozens of developers find hard to utilize because it requires a lot of code writing to finalize every task and follow the structure of XML for every message sent. Since REST makes data available as a resource, it follows another logic. Every single resource is represented by a unique URL, and one can request this resource by issuing its URL.

The web application programming interfaces that adhere to the architectural constraints of REST are known as RESTful APIs.  To work with resources APIs utilizes HTTP request such as GET, POST, HEAD, PATCH, CONNECT, PUT, TRACE, DELETE, and OPTIONS. The systems of RESTful systems support different formats of messaging such as HTML, X ML, JSON, YAML, and plain text when SOAP only permits XML. One of the things that make REST prevail choices for public APIs building these days is the ability to support multiple formats for the exchange of data and storing.

Traveling companies along with social media giants issue external APIs to enhance the visibility of their brands even more. For instance, Twitter contains numerous RESTful APIs; Expedia contains both RESTful and SOAP APIs for its partners. JSON is known to be a lightweight and easy-to-use text format for the exchange of data. Every single file of JSON has a collection of values or name pairs and an ordered list of values. The format can be habituated with any type of programming language since these are universal data structures.

GRPC

GRPC is an open-source API framework that is universal and is classified under RPC. Google released GRPC publicly in 2015 thus newer than SOAP. The client software can call methods directly from the application on the server located on a different computer with GRPC. This allows the easiness of distributed service and application creation. Similar to REST and SOAP, HTTP is the GRPC transporting layer. However, like RCP, GRPC permits developers any kind of functional call definition rather than selecting from predefined choices such as  GET and PUT in the REST case.

The GRPC by default makes use of protocol buffers instead of XML and JSON as its interface definition language for structured data serializing. In this case, developers require to define the data structure first that they want to serialize. Once the specification of the structure of the data has been executed, they make use of the protocol buffer compiler to produce access to the data classes in the programing language you choose. Then, that data is compressed and in binary format serialized at run time. GRPC is widely utilized for communication amongst micro servers because of its availability in multiple languages and its performance is high.

Graph QL

The urge for faster development of features, and more effective loading of data due to maximized mobile adoption, along with a large number of clients, prompted the developers to look for other approaches to program architecture. It was generated in 2012 by Facebook for internal use. It’s the unexampled REST, with organizations like Yelp, GitHub, Coursera, Shopify, and the New York Times utilizing it to create APIs. GraphQL is an API query language that permits the client to detail the exact data it requires and simplifies the aggregation of data from multiple sources; therefore, developers can simply utilize the API call to ask for required data. GraphQL uses another special feature that uses a type system to describe data. The application that makes use of GraphQL manages what data it requires to acquire from the server. This permits them to run fast even when the connection of the mobile is slow.

CONCLUSION

Considerably, the role of APIs is greater if looking at it from the angle of software development but also the angle of business collaboration. These machine-readable interfaces for the exchange of resources are just like services of delivery that work under the hood and activate the required technological connectivity. Eighty-three percent of participants still find the integration of APIs critical to their IT infrastructure and enterprises according to the Fourth state of API integration report of 2020. In this regard, decision makers along with developers have two main tasks to select the API that effectively works for an industry or organization’s specific business needs and understand how to efficiently make use of it.

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