Intro to API testing?

Posted in: Quality assurance testing by: Simon on:

Making software that your target audience will love is no easy feat; after all, even the most brilliant application won’t do anyone much good unless it is carefully planned, structured intuitively and seamlessly implemented. Here we will look at what an API is, how it is tested and why it matters.

What is an API?

An Application Programming Interface (API) deals with the core functioning of a program and is made up of a collection of protocols, tools, routines and procedures which together determine how components interact with each other. While API usage first started out as a way to facilitate integrations with a set of closed distributed systems it has evolved considerably over the years and now plays a key role in multi-use integrations with both internal and external systems.

How does API testing work?

API testing takes place at the business or logic level of the software architecture and validates the complete functioning of a component by conducting a number of targeted tests. Basically, an application is used to send ‘calls’ to the API which triggers various responses and these outputs are then recorded and analyzed to determine reliability, functionality, security and overall performance. Service virtualization is also often used to isolate the services being tested as well as to expand the test environment.

API testing can be summarized into the following three categories;

  • Positive tests – Determines whether the software does what it is meant to do
  • Negative tests – Measures the software’s ability to deal with error conditions
  • Robustness tests – Tests for speed and timing issues

The benefits of API testing

API testing provides an extremely effective way to ensure that a component is working properly before it is integrated into other products and applications. The following are some of the many benefits;

  • Verify correct performance across various operational environments
  • Ensure that response times are acceptable
  • Determine maximum load capacity
  • Understand how, why, when and where software failure occurs
  • Reveal potential opportunities for improving user-experience

Who needs API testing?

APIs can encompass almost any computer-to-computer interaction; therefore, API testing is essential for any developer interested in ensuring that their software is working effectively. One of the most common uses of APIs nowadays is to support mobile app development, which makes testing vital to the delivery of all manner of mobile technology ranging from mobile phones to tablets to smart wearables. This unique form of software testing is also particularly valuable for organisations that use multiple developers or embrace a continuous integration (CI) process.

Having your applications running smoothly is essential to the success of your business and API testing offers a reliable way to confirm that all is well. Apart from helping to provide a quality user-experience, scrutinizing the inner working of your programs will also ensure that you have a solid foundation to build upon in the future. For best results, have your software API tested rigorously and regularly.





Simon is the founder of Crowdsourced Testing. After 10 years in interactive software development, he set his sights on building a world-class crowdsourcing platform to facilitate the software testing process for developers.