Tuesday, June 25, 2024

(API testing is one of the most crucial steps in software development)

The API testing market has experienced a significant surge in recent years, driven by the expansion of digital technologies and growing reliance on the application programming interface for efficient integration among various software systems.

Testing is imperative for various reasons, such as quality, security, cost-effectiveness, fulfilment of customer requirements, reliability, and understanding of performance. As we know, software undergoes various testing steps before reaching its final iteration. Software testing determines quality and performance. It plays a crucial role in the seamless operation and integration of different software components. 

It was already prevalent, but its significance has increased recently. The Demand for API systems is growing every day with the growth of the mobile development industry.  Immersing in a tech-savvy world has become more interesting with the rising number of software. It ensures that all the functions operate together from end to end.

API testing

Testing is a standard process for developing any product that helps make a product better. However, every product needs a specific type of testing that best describes the quality of products. For example, functionality testing can work on a website, but security testing will ensure optimum quality. Many types of QA testing are prevalent in the market, ensuring the best quality products through all the endpoints. It is a quality measure that meets the testing of today’s complex applications.

What is API testing?

Application programming interface, is a type of QA testing that ensures software functionality, reliability, and performance. It’s essential for automatic testing because it serves as the primary interface for the application logic. API can be understood as the set of rules and protocols that allow people to interact with each other and exchange data and services. 

It ensures that APIs work correctly and provides accurate and expected results. Developers can run API tests automatically or with the help of automated tools. Several API tests determine the functionality and performance of the API interface. Each test is crucial in testing the API and ensuring its reliability. 

The API process involves testing the endpoints, functions, and interactions with other APIs.  These steps include various types of testing, such as function, security, performance, and more. 

Traditionally, API testing is performed by developers, quality assurance engineers, and specialised API testers who are well-versed in the field.

Scope in the future

As far as the API testing tools are in demand, it will continue to grow and evolve. It plays a vital role in ensuring the quality of software. The future of API is focused on delivering more reliable and secure software.

Adopting an API as a testing method will be increasingly common. According to a report, 32.9% of developers have begun defining development.

Software bugs are common, and one has to ensure the software system is free of bugs and glitches. The software industry is aware of these risks. Therefore, they’re giving software testing more importance than anything else.

The software industry has grown tremendously in recent years. Testing has advantages in ensuring that software is free of bugs.

API has become the backbone of modern software and integration. As a business, the adoption of digital transformation for seamless communication and systems will continue to grow. This increased demand will also increase its growth potential to ensure the functionality, reliability, and security of these APIs.

As we progress, the future of API testing will grow prominent as the applications that rely on the software will also grow continually. With the development of mobile devices, reliable APIs are also being developed for software testing. Companies are also moving towards a microservice architecture, and the need for comprehensive API testing will also increase.

Today’s software landscape is competitive, and users are unwilling to tolerate unbelievable applications. Even a minor issue in the API layer can lead to errors and latency, negatively impacting the business. This puts pressure on the developer team to deliver APIs that are free from errors and highly efficient.  

Serval developers tackle this challenge by choosing an API-first development model. In the API-first development model, applications are conceptualised and created with a collection of internal and external services. This emphasises the importance of API’s infrastructure, which defines the API quality.  It is crucial, enabling the team to continuously verify the quality and performance of software and offer a seamless digital experience.


It offers several benefits in the modern software development process. Here are some of the top benefits.  

Quality assurance:

API provides quality assurance to companies and retains business reputation by enabling teams to ensure their API performance. 

Early detection and resolution: 

One of the top benefits of API testing is the early detection of defects. This makes the development process easier and helps the team to stay on the curve.

Consistency performance:

It ensures the consistent performance of applications and software by checking the critical factors, such as response time, latency, and thoroughness, required to maintain positive performance. 

Why is it necessary? 

It is critical for back-end testing in the software development process. UI tests do not often reveal complete functionality and crucial elements of back-end testing. This can leave bugs and errors within the server that can negatively impact the product, delaying its release date or requiring large texts to be written.  

On the other hand, API testing allows developers to start testing in the early development cycle before the UI layer. It finds the bugs in the earlier stage of development and repairs the problem before they impact the UI.  This also saves time and prevents more severe level bugs that affect the product. Moreover, it also helps developers make requests not present through UI. 

An API approach is more useful in a microservice’s architecture. Many companies use Microservices for software applications as they can be deployed efficiently. In the microservice’s architecture, each section of the applications operates individually. Each section consists of its data and commands with the data store. API testing allows seamless communication and efficient management between microservices.

In companies following the Agile approach, API testing helps with feedback and makes the development process more manageable. Overall, incorporating API tests is helpful in the development cycle, assisting developers in handling the development process efficiently. 


API is an essential step in the software development process. While performing API tests, developers can choose a range of AI testing tools or frames to ensure the API interface works seamlessly. API Test allows developers to customise the test as they have a vast range of plugins with specific capabilities. Testers can pick from various libraries that they find appropriate for their coding.  This allows them to build unique reporting standards and use complicated logic.  Still, testing required coding skills to design their framework.

API testing tools are easy to use and provide an intuitive interface with minimal coding that less experienced developers can deploy. However, there is only one downside of API testing. More specific problems go unnoticed as they are designed to detect general issues.

API testing tools provide user-friendly interfaces with minimal coding requirements, enabling less experienced developers to deploy the tests. Unfortunately, since the tools are often designed to analyse general API issues, more specific problems with the tester’s API can go unnoticed.

A wide variety of testing tools are available, from paid to free, offering unique solutions. The global API testing market is expected to reach approximately $4 billion by the end of 2030. Some common examples of API testing tools are Insomnia, Assertable, ReadyAPI, Swagger UI, and Katalon.


For example, Apache JMeter is a free, open-source Java application that works on Windows, Linux or macOS. The tool doesn’t require programming skills and can handle many different types of applications, servers and protocols. JMeter can use comma-separated values files to generate heavy loads of realistic traffic to put APIs under pressure. It enables admins to build API testing into continuous integration/continuous delivery (CI/CD) pipelines and to use JMeter for API monitoring.

Likewise, the Apigee tool, part of Google Cloud, supports the designing, building, testing, deployment and monitoring of APIs by enabling developers to track traffic, error rates and response times. Users expose their APIs on Apigee, which decouples the app-facing APIs from back-end services so that the apps can keep calling the APIs without interruption despite any code changes on the back end.

As a third example, Insomnia is now part of an open-source API client for creating, organising, sharing, and executing requests from a Mac, Linux, or Windows desktop application. Insomnia users can create customised API test flows, including chained requests, with Insomnia’s test suite scripts. Insomnia’s code editor is relatively simple but requires some coding skills. Also, the app’s command-line interface lets users integrate automated Insomnia API tests into their CI/CD pipelines via GitLab or Bitbucket.

Common bugs that API testing can detect

API testing can typically detect software bugs such as the following:

  • API reliability issues.
  • API response times.
  • Duplicate functionalities.
  • Exceeded request limits.
  • Incompatible error-handling mechanisms.
  • Incorrect errors and warnings.
  • Incorrectly structured response data.
  • It needs to include functionalities.
  • Multithreading problems.
  • Security problems.
  • Unused flags.

Challenges in API testing 

Several challenges are encountered while working on API testing. Some of the common challenges are:

Setup of API testing:

The initial setup of API testing is quite challenging, not because it is difficult but because it is a very time-consuming. No GUI is available, so it differs from other software testing environments. The database and server configuration must be done based on the application’s requirements. The quality assurance team has to work on various aspects to perform testing, including getting access to the testing system, getting security approvals, and overcoming the developer’s resistance. 

The team can perform it when the initial setup is completed. This setup process may take one or more days.  

Sequencing API calls:

The API calls must appear in the specific sequence to get the desired results. But sometimes, calls might appear in a different sequence. This usually happens with multi-threaded apps. The tester will need help to check if the system works correctly, as haphazard could lead to confusion. 

Selecting, Testing, and Validating the Parameter Combinations:

APIs assign data values to parameters. These parameters pass through the data requests to manage communication between the systems. Sometimes, the API would assign two different values to the same parameter.

The QA team must test all possible parameter combinations in API to identify any issues with specific configurations. They also need to check if it passes the validation criteria.

Updating the Schema of API Testing:

Throughout the testing lifecycle, the QA team must ensure that they maintain the API testing schema, reflecting any program changes that result in additional parameters for API calls in the schema configuration.

How To Approach API Testing?

Approaching API testing involves the following steps that are mentioned below:

  1. Define the Scope of Testing

The QA team must first define the scope of testing. The available endpoints for testing, the error messages to display if the request fails, and the running components in the application comprise the essential information. It includes asking essential questions such as. List all tests required to complete the preparation and use of tests. Determine who will perform API testing and how often.

  1. Set up the environment and integrate application data

Once you determine the scale, set up the testing environment, set up data and servers as per application requirements, and provide a request file with API testing to test it against each configuration.

  1. Implement various testing methods

Perform various tests, such as functional tests, load tests, and security tests, to ensure that the API works properly. Each has a specific purpose, and hence, testing is done well before going into production. Before you begin testing, make API calls to verify that the it is working and test each communication to verify that it provides the desired results.

  1. Choose a good API testing tool

Choose a tool that can perform API testing well. Discuss different tools with the developers and QA team, determine their pros and cons, review the programming languages ​​they follow, and evaluate whether they fit the budget. Consider using codeless API test automation tools to automate and enable business users to run tests without writing a single line of code.

  1. Create tests and analyse results

Write and execute test data and check whether actual results match expected results. For example, check the behaviour of the API in the system when the response does not return a value or if the response time is within the accepted range. Verify that the API can meet client needs and run smoothly across browsers and devices.

  1. Document Maintenance

When performing test documentation, save the results for future reference. Also, update the documentation regularly to avoid any recent or retroactive changes affecting the API.


API testing is becoming prevalent in the software and QA chain as standard software. It is required to ensure the best product quality, ensuring multiple factors like security and performance.

This testing offers many advantages compared to any other type. It is designed to verify all smooth and broader test coverage components. API tests are faster and more accurate than UI tests.

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