Ilya Dudkin 23/04/2019 #QA #Tips 9 min read Load testing is finding out how a system will perform in real life conditions. This offers a lot of insights into how an app will perform when many people are using it all at once and will identify a lot of other things such as: The app’s top operating capacity Find out whether the infrastructure in place is enough for the app to perform correctlySustainability especially in terms of top user loadsThe number of users the app can support at once Finding out all of these things is essential because if an app or website is running too slow, it can harm the bounce rates, conversions, and revenue. Some institutions in industries such as retail and banking might have thousands of people online at the same time, and any downtime might cost these businesses millions of dollars in lost revenues. This is why it is important to test website speed and make sure it can handle the necessary workload. Load Testing Tools for Web Applications There are five main tools that are used for web application load testing: The Grinder Gatling TsungJmeterLocustEven though these are the most common tools, web load testing software can be divided into two categories: on-premise and on-demand testing tools. The on-premise tools are the ones that can be deployed on a customer’s local infrastructure. These tools are usually open source which means they are free of charge while there will be some commercial solutions which require you to pay a license fee. If this tool finds an issue, it will get a support specialist involved who can fix the problem. On-demand testing tools, sometimes called SaaS, are cloud-based thus allowing customers to avoid all the hassles that come with handling local load testing farms. The significant benefit here is that you pay only for what you use and there are no maintenance tasks. A company that is developing a website application might choose to use both SaaS and on-premise to have the best of both worlds.The Load Testing Process The process of website testing looks like the following: The necessary testing environment is createdThe load testing scenarios are determinedThe load testing transactions are determined Perform the test scenario and assemble the necessary metricsResults analysis and making recommendations Making adjustments to the systemRe-test (if needed) If you have no previous experience with web application performance testing, you will probably encounter a lot of hurdles. The first thing that you want to do is set a realistic load pattern for your test. Keep in mind that even if an app is in the production stage, there is a good probability that its usage has changed over time. For the services that have not yet reached production, you will be able to use Little’s Law to figure out the load pattern. If a productive environment is already in place and users are already taking advantage of the new services, try looking at the log files to figure out the customers’ interactions per hour as well as how many concurrent sessions there are. Another problem can be picking the right user simulation. If you decided to go with an open source tool, be especially careful here because they are known for providing little simulation support. Instead, they will give you a protocol-based load generation. To avoid this problem, try choosing a web-based tool that loads the content as the user is clicking through a different page. Many of these activities can be encompassed in the protocol level since client-side processing is not considered at all. Therefore, before you decide on which user simulation approach to take, it is a good idea to take a good look at your app under test conditions. Today’s web apps usually need a real browser-based user simulation method. Also, it is a good idea always to keep reminding yourself that your goal of providing the best possible performance is more of a journey. The longer it takes you to notice the errors in development, the more work it will take to fix them. Begin with component load testing during the development process and use benchmarks to locate breaking points. Once you discover them, try switching to more complex real user-level testing scenarios during the QA as soon as the app was integrated with the surrounding systems.Conclusions Web application performance testing is necessary in order to find out how the app will perform once it is released to the public. While it is hard to account for every single situation, you should plan on testing your app with as many concurrent users as you see possible since you want to avoid situations when the app is crashing. This process will allow you to determine some of the bottlenecks that exist in performance which can prevent future scalability and stability. During the development stages, you need to have a scalability plan in case the number of users far exceeds your estimation. While this may seem like unnecessary costs, the amount of money that you will end up losing if your app goes viral, but crashes under pressure will be even higher. That is why it always a good idea to take every precaution in this regard. Also, if you do not have the necessary programming knowledge to use some of the load testing tools, do not let this prevent you from conducting load testing altogether. There is no point in having a great app if no one can use it. Therefore, always try to enlist the necessary help during the development process to make sure that all of the bottlenecks have been eliminated and your app will be available to a mass audience. If you need help with this, there are plenty of providers out there who are eager to help you.