The significance of API testing is crucial for determining the product’s quality and CI/CD processes. API tests can easily cope with the short release cycles and frequent changes taking place without breaking the test types, unlike GUI tests. 

It is a kind of software testing analyzing the application program interface which in turn verifies its functionality, performance, reliability, and security. Sometimes, these are performed directly on the API and sometimes as part of integration testing. 

It enables two software programs to communicate with each other. The way applications request services from the operating system or other applications is determined by the code. Let us know more about the API automation, testing tools and its benefits in the post mentioned below. 


API Testing 

The application program interface usually has three layers: data layer, service layer, and presentation layer. The API layer is where the users can interact with the services, functions, and data held within the app. 

The main emphasis of API testing is on analyzing business logic along with the application security and data responses. Simply make a request to one or more API endpoints for performing the API test and compare the response with the expected results. 

It is the DevOps, quality assurance, and development teams who make use of the API testing for testing practices. 


Kinds of API Tests 

Whether the application programming interface is working appropriately or not is determined by the varied types of API tests. These can be general and specific both. Let’s have a look at different kinds of API tests. 

Validation Testing 

The foremost kind of API test is validation testing. There will be a few sets of questions in this that will be addressing the whole project. One set of questions will be concerning the product like whether the product was built correctly or not. 

The second set of questions relates to the API behavior. The questions will be like: Is the data processed in API correct or not. Lastly, the third set of questions concerns the efficiency of the API. The efficiency and accuracy of API will be tested in the third set of questions. 


Load Testing 

How many calls an API can handle is determined by the load testing. The test is either performed after a specific unit or the entire codebase. It is also used to figure out whether the theoretical solution can work as a practical one under the load or not. 


Functional Testing 

Next comes functional testing. It ensures the performance of the API like it should work exactly as it is supposed to perform. During this, specific functions are analyzed within the codebase to confirm whether API can handle errors outside the designated parameters. 


Security Testing 

Security testing is often conceived following penetration and fuzz testing. There are aspects of both kinds of testing in this. It also validates the encryption methods the API uses along with the access control design. In addition to this, it also includes the validation of authorization checks for user rights management.


Reliability Testing 

Reliability testing ensures that the API is producing consistent results and building connections between the platforms constantly or not. 


Fuzz Testing 

It inputs a huge amount of random data forcibly which is known as fuzz or noise testing. It attempts to create negative behavior like forced cash or overflow. 


API Testing Tools 

The developers have an option of either writing their framework or choosing from a wide range of API testing tools while performing a test. The developers can also customize the test. While creating the test, there are no limitations on specific tools or their plugins. 

The testers have the choice of adding the library they consider most appropriate for their coding platform. Not only this, but they can also build unique reporting standards and incorporate logic into the tests. But for all this, the testers must have the coding skills to design their framework. 

API testing tools also provide user-friendly interfaces with fewer coding requirements. This enables the developers to deploy the tests easily. The API testing tools are designed such which analyze the API issues and problems which usually go unnoticed. 

There is a range of API tools available out of which, some are paid whereas others are free. Here are some of the API testing tools for the developers. 

Katalon: It is a comprehensive desktop and mobile testing tool for beginners and experts. This tool is considered best for automated testing. 

Accelq: It is a cloud-based continuous testing platform. The tool is considered best for codeless automation logic, complete test management, and API regression planning. 

ReadyAPI: The next best API testing tool is readyAPI. Whether it is functional, load, security testing, readyAPI is the tool. 

Postman: Another API development environment is the postman. It is a Google Chrome app used for verifying and automating API testing. 

Apache Jmeter: It is an open-source tool that is considered best for load and functional API testing. 

Rest assured: Rest assured is a kind of tool which carries out the testing services in the Java domain. It is a free tool and anyone can easily use it to test the rest API. The entire lifecycle of API depends on this tool. This tool is best for API design. Moreover, it is free and can be used by users easily. 


Challenges while Implementing API 

Quality analysts face numerous challenges while trying to implement the API test framework in an organization. Let’s discuss all those challenges one by one to overcome them. 


Selecting Right tool 

The most common challenge every quality analyst seems to go through is regarding selecting the right tool. These days, the number of API testing tools available in the market has increased way too much which makes it difficult for the analysts to decide which one to choose and which one to leave. 

Usually, the testers like to proceed with the latest and most expensive tools available in the market. But the tool is of no use if it fails to bring you the desired results. Consequently one should always make room for such tools which address your requirements based on the company’s needs. 

Some of the popular API testing tools include postman, Parasoft, load focus, pingAPI, and the list goes on. 


Learning curve 

The approach of API testing is different from others consequently, it is crucial to figure out the learning curve. The learning curve has to be minimal if you are hiring experts either in-house or consultants for API testing. Make sure the specialists have product and application knowledge. 

The learning curve may change from medium to high depending on the tool of choice if any existing team member is assigned the task of API testing. Whether the analyst has tested the application before or after also decides the learning curve of the particular product or application. 


Skills set 

The skills set has a direct connection with the learning curve mentioned above. The tester would require to change his approach and equip himself with the knowledge of new tools if the tester was changing from GUI-based testing. 

For instance, if the API testing is to be done in a JSON approach, then before proceeding, the tester will have to learn this tool or framework and then create the tests. 


Test specifications 

The testers need to be familiar with the expected test results to test an application effectively. But this, in reality, seems to pose a real challenge as for this to be carried out, the testers need clarity over the precise requirements. 

Being unclear about the test’s requirements will take you nowhere and might complicate your testing job. Consequently, do devote some time to learn about some missing test specifications and then begin with the same. 


 Significance of API Testing 

Some testers and analysts insist on performing the user interface tests but these tests are inefficient for validating the API service functionality. Not only this, but these also do not cover the necessary aspects of backend testing. All this can result in bugs which might hamper the results. 

Consequently, the developers choose to do API testing. With the API testing, it becomes easy for the developers to start early. Going this way, the developers kill at least half the bugs before they convert into some grave issue. Besides this, the developers can make requests for exposing security flaws. 

API testing kit is an integral part of agile software development where you need feedback for a smooth process. As compared to the graphical user interface, unit tests and API tests are preferred in agile environments. It is because they are easy to maintain and more efficient. 

Consequently, incorporating API tests is integral to the test-driven development process. It is because it can benefit engineering and development teams throughout the whole development cycle. Lastly, due to all this, the customers end up getting the best services and superior quality products. 



There is no doubt in this that API-based applications have gained popularity in recent years because of their scalable nature. Their integration into the other applications is also easy. Unless you test the API testing kit properly, it may cause you problems not in the API application only but also in other applications. Get in touch with our testers to get the testing done right.