What is Application Programming Interface? An Easy Guide for 2021

Ajay Ohri


The application programming interface is a big part of the web. Companies investing in this new area of business, possessing a working understanding of APIs becomes increasingly relevant to careers in the software industry. The ‘P’ in API stands for “Programmer”, not “Program”, to highlight the fact that APIs are used by programmers, who are humans. API stands for application programming interface, a concept that applies everywhere from command-line tools to enterprise Java code to Ruby on Rails web apps. An API is a way to programmatically interact with a separate software component or resource.

  1. What is Application Programming Interface?
  2. Role of Cloud Computing of Load Testing
  3. Types of Application Programming Interface
  4. Design of API
  5. Public API Implication
  6. Documentation of API
  7. Examples of Application Programming Interface
  8. Tools Used for API Testing

1) What is Application Programming Interface?

Application programming interfaces hide complexity from developers, extend systems to partners, organize code, and make components reusable. An API is defined as a specification of possible interactions with a software component. The API layer is used to shield the outside world or your clients from knowing the structure, organization, or even what exact service.

2) Role of Cloud Computing of Load Testing

  • APIs make the platform extensible which can lead to a rich feature set. They also speed up the platform access and direct more efficient management of platform security.
  • They also help co-opt with other service providers. APIs ensure compliance and help with successful integration and interoperability. They make handling analytics an easy task.
  • A successful cloud provider knows better than to overlook the importance of APIs, this mistake can bring large companies down.
  • The most important aspect of successful APIs is that they ensure data portability and interoperability.
  • A web service cannot be called a cloud service if it does not have an API. Or, in other words, a web service without API is SaaS – not could service.

3) Types of  Application Programming Interface

The different types of API are:

  1. Private APIs: is designed for improving solutions and services within an organization. In-house developers or contractors may use these APIs to integrate a company’s IT systems or applications, build new systems or customer-facing apps leveraging existing systems. The private strategy allows a company to fully control the API usage.
  2. Partner APIs:  are openly promoted but shared with business partners who have signed an agreement with the publisher. Used software integration between two parties. A company that grants partners with access to data or capability benefits from extra revenue streams. At the same time, it can monitor how the exposed digital assets are used, ensure whether third-party solutions using their APIs provide decent user experience, and maintain corporate identity in their apps
  3. Public API:  these APIs are available for any third-party developers. A public API program allows for increasing brand awareness and receiving an additional source of income when properly executed.
  4. Commercial API: users pay subscription fees or use APIs on a pay-as-you-go basis. A popular approach among publishers is to offer free trials, so users can evaluate APIs before purchasing subscriptions.

4) Design of API

The design of an API has a significant impact on its usage. The principle of information hiding describes the role of programming interfaces as enabling modular programming by hiding the implementation details of the modules so that users of modules need not understand the complexities inside the modules. Thus, the design of an API attempts to provide only the tools a user would expect. The design of programming interfaces represents an important part of software architecture, the organization of a complex piece of software.

5) Public API Implication

A public API can sometimes declare parts of itself as deprecated or rescinded. This usually means that part of the API should be considered a candidate for being removed, or modified in a backward incompatible way. Therefore, these changes allow developers to transition away from parts of the API that will be removed or not supported in the future.

6) Documentation of API

Documentation is crucial for the development and maintenance of applications using the API.API documentation is traditionally found in documentation files but can also be found in social media such as blogs, forums, and Q&A websites.

7) Examples of Application Programming Interface

These are some of the important API examples:

  • Rich weather snippets seem to be commonplace, found on all platforms, like Google Search, Apple’s Weather app, or even from your smart home device.
  • Log-in using Facebook/Twitter/Google/Github functionality you see on so many websites.
  • The “Pay with PayPal” functionality is built with APIs to ensure that the end application can only do what it needs to, without being exposed to sensitive data or gaining access to unintended permissions.
  • Twitter bots are accounts that automatically tweet (or retweet), follow, and send direct messages based on software instructions. There are loads of bots on Twitter.
  • APIs are great for travel services since they make it easy for machines to quickly and autonomously exchange both data and requests — in this case, trip availabilities and reservation requests.

8) Tools Used for API Testing

The right process, tool and solution for API automation test are more critical than ever. API testing is a crucial component of a success CI/DevOps practice, Tools covers both open-source and commercial solutions that testing.

  • Katalon Studio is a free test automation tool for API, Web, Desktop App and Mobile applications. It is emerging as a leading tool for API/Web services testing and positioning itself as a comprehensive end-to-end automation solution for both developers and testers.
  • SoapUI is a headless functional testing tool dedicated to API testing, allowing users to test REST and SOAP APIs and Web Services easily.
  • Postman is a good choice for API testing for those who don’t want to deal with coding in an integrated development environment using the same language as the developers.
  • Tricentis Tosca is a continuous testing platform for Agile and DevOps.
  • Apigee is a cross-cloud API testing tool, allowing users to measure and test API performance, supports and build API using other editors like Swagger.

·JMeter is widely used for functional API testing although it is actually created for load testing.


Building a successful API is an art, comprising business analysis, technology architecture, software development, partnership, content writing, developer relations, support, and marketing. It takes a village to build a good, popular API.

Jigsaw Academy’s Postgraduate Certificate Program In Cloud Computing brings Cloud aspirants closer to their dream jobs. The joint-certification course is 6 months long and is conducted online and will help you become a complete Cloud Professional.

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