What is an API? | DeviQA
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What is an API?

By on 2019-07-29T00:00:00.000Z

API is an abbreviation for Application Programming Interface. APIs are built-in functions that software developers embed to add a new feature to their application.

For a better understanding, take an example, Google Maps is a service by Google; you probably have seen many other websites also have ‘Google Maps' displayed on their website. This happens by just embedding Google's Map API to their websites. Developers need not program maps on their own. Thus, APIs save developers a lot of time and effort.

When need to login, some websites offer ‘Login with Facebook' or ‘Login with Google+'; how does it happen? It is because Facebook or Google's Login API is open source, that other websites use. We could say it an API connects and communicates between two applications. There are many real-life examples of APIs we will read further in this article.

What can APIs do?

APIs act as a universal connector between services and tap into databases and servers. APIs also have software to hardware relation that controls permissions by hardware to software. Let's say, a website you are using is asking you to expose your location, this application will reach you by geolocation API in your browser. All the websites are not permitted to access your location or other information so, they access it via APIs, that's why they say APIs control access to resources and play an important role in application security.

Mobile operating systems iOS and Android are also using APIs. Many applications let say photo editing apps ask for granting access to mobile's camera. When developing such apps, developers use the camera API, now the user has the authority if he denies permission the app cannot use your phone's camera.

APIs can share properties:

Here properties stand for data, code, features, service or any element that a software/web development company wants to share with other developers. APIs are the best example of open source code.

APIs can share a part of Server:

No developer or company would like to expose its entire software and its source code, so, here they go with APIs that only reveal the part of source code a developer wants.


End Users are stakeholders who only get benefitted by APIs while developers are the people who actually use APIs. A software developer needs the API to embed while creating an app and he has the opportunity to reuse the already built software components.

APIs can increase compatibility:

Applications empowered with APIs possess more compatibility with different devices and operating systems. APIs provide tremendous flexibility and make the user experience richer and more intelligent.

Types of APIs and when you need to use them

There are typically two types of APIs, Web APIs, and Web Service APIs.

Web APIs

Web APIs are that are being used over the internet via HTTP. One can achieve a web API by consulting either JAVA or .NET frameworks. Purpose of web APIs is adopting an application's capability to our web application. Below we explain web APIs;

Public APIs: APIs of this type are all allowed to use as a public property, there is no restriction to access them. They are also called Open APIs.

Shared APIs: also known as Partner APIs, they require a license by their owners to use them as they are not available openly.

Internal APIs: as the name suggests these APIs are limited to an internal system and owned by a company. They are specifically developed to use by the team members and different departments of a company.

Composite APIs: these are the APIs that combines 2 or more services by different applications. Embedding Twitter's notification on your website is an example of a composite API. They speed up the execution and provides better user experience.

Web Services

A system or application working via protocols that use a URL to provide access to its own services is called Web Service API. Famous examples are SOAP, SOAP XML-RPC JSON-RPC

Benefits of API. Why do you need an API for your application?

APIs have many benefits for both developers and end-users. For example:

Productivity: APIs saves the efforts and time of building different features from scratch. It results in more productivity and quicker completion of projects.

Flexibility: access to information and services is enhanced by the use of APIs. APIs inter-connects the applications that make delivery of service more flexible.

Better Sharing: Applications can share their components with each other which brings satisfying user experience and APIs permitted content is automatically available i.e. Google's Map API.

Integration: APIs enable services to be embedded from one site to another. It creates a flow and an environment of collaboration.

Adaptation: versions change, applications keep on getting updated, the API technology helps in data migration and transfers the information in its real form.

Samples of real-life APIs

There are hundreds of thousands of APIs being used by almost every tech company. From Amazon's API for the affiliate program to Google's map and translation APIs, there's a big list. However, we describe some major samples of real APIs here.

Slack's Messaging API:

Slack API

A company Slack provides Real-Time Messaging API that one can use to have a message sending/receiving module on their application.

Instagram's API:

Instagram API

Become a client of Instagram and get their API. It will allow real-time notifications on your application by the users who authenticate your application.

Amazon's API:

Amazon API

Beside the AdSense bloggers are now a day have tended to affiliate marketing. In which they create an affiliate account on Amazon, amazon approves them their API. This was they give links to amazon products in their blogs when a product is purchased via this link the blogger receives a commission. All this happens because of an API.

Google's Map and Translation APIs:

Google API

Web applications such as Booking.com use google Map's booking API to check the availability of rooms in hotels. Same is the case with Google Translation API which is used by different websites to give a language translation feature.

Testing of API

So, we have established a great understanding of "what an API is, why to use it, what are the types and real-life samples", now we will learn what is API testing and why it is necessary.

Like other software applications, APIs are also tested to determine if they meet the expected requirements, ensures reliability. They also go through a performance test.

Unlike the other software APIs don't possess the user interface, so, they are tested in back-end perspective. As APIs are the foundation of many web services, that's why their testing is so imperative. The downfall of an API will cause breakdown for many applications. Hence, testing an API is mandatory. Our company has huge experience in providing API testing services, so if you need to test your api - contact us!