In the past, APIs (Application Programming Interfaces) would usually serve as integration points between internal systems. But with time, its function has changed in the bigger picture of software applications.
APIs are now a fundamental part of any company’s central system, an integral part of the client (both web and mobile) application design. For their past, back-office oriented use, which was mostly related to handling reports, the performance factor of APIs was never really an area in focus. However, now they function at a middle space between the end-user and the service offered by an organization. The performance factor, therefore, has become a critical matter that needs to be subjected to specific standards.
Your API data sources need to have a prompt response and a certain level of performance reliability. Otherwise, they can undo the advantages your properly built front-end applications bring to the table. APIs make up a network of microservices- multiple of them combine to make up the source of client application functions.
Like any other system where the required standards are met through identifying its core metrics and qualitatively testing and altering the system, for APIs, the standard performance level is achieved through load testing or stress testing.
Why is API Testing Important?
The most prevalent use of APIs by web client platforms as well as Software as a Service (SaaS) companies is in enabling their end-users to have access to the data existing on their platforms at their convenience. This ensures that end-users do not need to rely solely on the default interface.
APIs work to make machine-to-machine communication possible by employing languages and file formats that follow industry standards. Users can also merge in different filters and outputs on the dashboards and customize the applications, along with having access to automating the more textbook functions.
APIs are a powerful tool that allows cross-platform data sharing throughout the internet. Organizations are harnessing this power by making different APIs that would let end-users access the platform’s data in a way that suits their specific needs. To today’s real-time data-based businesses, APIs are understandably a significant asset. It is understandable then why API testing is such a big deal.
Regardless of the type of the API –a RESTful application based on XML or JSON or a SOAP-based XML container- running tests is extremely important to assess the average time taken to respond and the accuracy of response. These two necessary tests need to be out of the way for you to approach the next steps, which are API load testing and stress testing.
- Load Testing: You must perform Load testing to ensure that the API can handle a certain number of simultaneous requests. This type of testing aims to check the volume of traffic that the system can manage without crashing and make sure that it is at level with the platform’s expected traffic.
- Stress Testing: Stress testing checks the upper threshold of the traffic limit that the API can handle. By increasing the simultaneous requests deliberately beyond the expected number, stress testing aims towards identifying the point where the system may crash and assess its recovery.
How do you perform API Load Testing?
For load testing, a QA professional will need to replicate several users using the application simultaneously, and the number of users will influence the API’s performance. The test scripts send specific requests to one particular endpoint and assess how the system functions under different volumes of traffic.
Usually, this type of testing uses multi-threading to send in several requests parallelly from one single workstation. You can set up multiple workstations if you see the need to imitate real-time user activity to collect relevant data. Both traditional and automated testing procedures, load testing is performed after completing the first testing cycle. For projects on a budget, it is more convenient to perform load testing near the end of the development phase after identifying most of the errors.
Load Testing APIs are integral to any organization’s business strategy as it rectifies slow server response, thus preventing customers from shifting to a faster platform. Users are likely to leave your app if it crashes amidst a function or takes too much time processing requests. It is not only about carrying the commands fast and smooth but also about maintaining the platform’s stability in the in-between stages.
Load testing also helps a QA professional assess how much at par the API is in terms of its expected functionality. It helps measure the best, worst and average response time along with the number of errors and the requests successfully processed by the system every second- thus ensuring that the app is ready for its target market.