What Are The Main Advantages to API Testing?


In the world of application development, Application Programming Interfaces (APIs) enables the communication and exchange of data between software. Testing your API is essential to the proper integration and delivery of quality software and product.

Unlike UI testing, API automation testing is designed to withstand the short release cycles and frequent changes that occur while using best practices for software development and IT operations. 

API testing is more important than ever. With the rise of cloud computing, API testing for interconnected platforms is essential to the success of all businesses and organizations in the cloud. 

What exactly are the advantages of API testing? Let’s take a closer look at what defines API testing as well as the API automation benefits to expect.

What is API Testing?

By testing the API, you are examining the security, functionality, reliability, and performance of your system. Instead of testing with standard inputs and outputs, API testing has the ability to get output directly from the programming interface and take note of how it’s responding. Instead of the simplicity of UI tests that focus more on the look and feel of applications, API testing has a deeper, more thorough understanding of how the architecture is built and works. 

In short, API testing is a smart move for general quality performance and data response. 

Types of API Testing

There are specific classifications of API testing to determine the performance of your system, such as:

  • Functional Testing. This involves testing functions within the codebase to determine if the API functions are working well within specific hardware parameters.
  • Validation Testing. The validation process occurs in the final stretch of the development process, validating that the correct steps down the path of development have been made. 
  • UI/Visual Testing. This focuses on how well the user interface is working, giving a status check on the visual aspects like the position and colors of elements. 
  • Security Testing. A process that checks to ensure the system is secure with encryption methodologies and authorization validation. 
  • Load Testing.  Load tests place real-world simulations and conditions for the SUT (System Under Test) to run against.
  • Runtime and Error Detection. This process focuses on monitoring, execution errors, error detection, and resource leaks. 
  • Penetration Testing. These vulnerability scans  take in a security experts perspective to spot potential loop holes and threats.
  • Fuzz Testing. This process involves placing random data in the system to detect forced crashes and other irregular behaviors. 

Benefits of API Testing

API application programming interface development technology conceptAPI testing has the ability to improve test coverage and efficiency, secure the system, and much more. Some of the benefits of performing this type of test include: 

1. Quicker Release

GUI tests have a reputation for taking longer to release products. However, API testing has proven to be the faster solution, saving up to eight hours of your time. This gives you a great opportunity to focus on other core aspects of software development

2. Better Test Coverage

It’s best to check how well-built a car is from the inside instead of its paint. Automated API testing drills down to the layers beneath the UI to ensure databases are communicating correctly between one and another. Ultimately, there’s just greater coverage, where system components are checked all at once. And, better test coverage means improved quality software and satisfied users. 

3. Ease to Shift Left

API testing can be implemented quickly – no GUI needed. Developers can easily shift left to get a head start, run tests, get instant feedback and resolve issues earlier on. Compared to UI tests, API tests take seconds, minutes maximum, to complete.

4. Lower Maintenance to Do

Changes in the API layers are rare. They are not prone to subsequent regressions caused by recent merges or releases but usually occur from major updates in the business logic. From the start, it’s best to reflect the APIs to-be-built in the specs and which functionalities they’re linked to.

5. Faster Bug Fixes

Since API testing works quickly to provide a solution, you’ll know right away if the results are good or bad. This can help you diagnose problems earlier on in the development of the system, allowing for efficient bug detection and removal. 

6. Reduced Testing Costs 

Because API testing covers more ground, is easier to maintain, and provides a quick release of results, the costs of testing reduce immensely. Your time, money, and resources can be utilized elsewhere. 

7. Universal Language Understanding

Since data is exchanged via XML and JSON formats, all languages can be used during API testing. So whether you prefer JavaScript, Java, Ruby, Python, or PHP, you are supported.

Best API Testing Tool

Feature highlights:

  • Easy-to-use UI and productivity-centric features for projects of all sizes
  • Supports REST, SOAP requests, and SSL client certificates
  • Enable test import from Swagger (2.0 & 3.0), Postman, WSDL, and WADL
  • Native CI/CD integrations (Jenkins, Azure DevOps, CircleCI, Dockers, etc.)
  • Data-driven testing methods better test coverage and reliability
  • AssertJ support to create fluent assertions in BDD style
  • Support API test data setup using UI testing 
  • Built-in reporting platform to centralize reports and activities across tool stacks: version control systems, CI/CD, test automation tools, and ALMs
  • Free API testing courses and tool tutorials on Katalon Academy


Are you ready to take a journey into the best API tools? Watch a demo of how our process works or sign up for API testing today.