How to do a website stress test

To analyze the performance of your website, in relation to its stability, you need to run a stress test. What is it and how to do it?

What is a stress test?

Generally speaking, a stress test means an in-depth analysis of your website in relation to a critical or extreme state: this usually coincides with having to deal with many incoming requests to manage correctly.

Although most websites are used to registering fairly standardized levels of traffic, there may be occasions (especially around events, such as Black Friday) where some eCommerce sites are called upon to face heavy loads. If your website hit an unexpected spike in a short period, would you be able to handle it? Stress testing is benchmarking to understand how a website performs in a specific circumstance.

What are the goals and benefits of a stress test?

Running a stress test allows you to view any errors that may have been missed in debugging, as well as generally allowing more control over any changes or nine features.

The objectives and benefits of a stress test are as follows:

  • Verify the tightness of the system when faced with situations where the load is extreme.
  • Identify the limit of users and simultaneous requests, beyond which the system no longer ensures stability.
  • Identify if the error protection-ready diagnostic system is displaying the appropriate messages to the administrator to allow for easier resolution of the problem.
  • Know and be able to implement any protective measures, such as cleaning up the source code.
  • Check the integrity of the data processed up to the moment of overload, to be sure of the functioning of the security and backup systems in place.
  • Test different hardware configurations like RAM, system processor, disk.
  • Check the website’s response speed to requests, giving the possibility to increase it to allow more simultaneous connections.

How do you perform a stress test?

In general, before carrying out the stress test, it is a good idea to set up a series of control points which allow for monitoring the stability of the system, its compliance with the standards it must satisfy, the requirements and the tools made available.

#1 Analyze the requirements

To perform a stress test it is necessary, first of all, to analyze the requirements that are intended to be met. The performances to be achieved are usually the analysis of the maximum workload that the site can support, response time and throughput. It may be a good idea in these cases to put all the dots in black and white, so that you can note any site reactions as the test progresses.

#2 Schedule the execution of the stress test

If the stress test consists of several points, it is important to set up the various tests including all the points to be touched, the environment in which it will be performed (i.e. hardware and software), the analysis of the resources used and the plausible outcome scenarios. Virtualizing and hypothesizing means playing in advance with the results, making it possible to prepare an easier problem resolution strategy should an unexpected one occur.

#3 Tool selection and stress test execution

Among the many tools made available for carrying out the website stress test – and presented below among the best in circulation – those to be used must be chosen using the classic formula of the relationship between cost/benefit (i.e. effectiveness in the case which the hypotheses to be examined with the test are many), also considering the coverage that the tool offers for the specific case of the test and the learning curve of the tool. Furthermore, the familiarity of the operator who will carry out the test with the instrument must also be taken into consideration: the better he knows it, the more effectively he will use it.

It will then be sufficient to follow the steps contained in the selected tool and note, case by case, each singularity or error displayed. In fact, it is necessary to carefully evaluate the script to be executed to overload the site in order to carry out the stress test effectively.

What are the best tools to perform a stress test? (additions)


Gatling is available in free and enterprise editions, both of which are packed with features. The Enterprise version has different features, such as a more intuitive interface, and supports a wider range of integrations.


It is a tool that provides extremely accurate data, closely emulating real users. It is capable of simulating dynamic variables and even based on different geolocation. The test begins with a predetermined number of concurrent users and can be adjusted gradually.

As the test runs, the report will show in real-time how response times are affected by these changing load conditions.

Apache Meter

This tool can simulate a large load on the server and also provides an analysis tool for various scenarios. The main purpose is to measure the resistance and strength of the portal.


Available in premium mode, it offers several tools in a comfortable and practical interface to use, allowing you to discover the performance and load you need for your purposes. Furthermore, a practical archive allows you to keep the results obtained close at hand, so that you can compare them.


Program with a free license (cd Open Source) is very spartan in the interface but comfortable and complete to use. Developed on Java, it can also be used by the most inexperienced.

blaze meter

Tool for creating complex reports with which it is also possible to evaluate all site performance, based on previously uploaded results.

How to analyze website stress test results

As mentioned, there are no right or wrong results on the success of a stress test but only those relevant to your needs. The test metrics under consideration, on which the analysis of the results must be based, are usually the response time, which displays how fast the system is in giving the results to the users and the maximum limit with which it is able to process them until the client no longer receives a response. Second is the quantity and quality of files or any other data that the user receives from the server and is called throughtput.

The utilization of the processor and of the memories, both volatile and physical, show the load peaks of the processing of the requested data, as well as the time of return to the user.

Finally there is the number of failed transactions: here you can see with certainty what is the maximum load that the site can support and beyond which it is advisable not to go.

Differences between stress test and load test

As mentioned, stress tests and load tests are two different things: the first is performed to evaluate the behavior of the site outside of normal conditions and has the precise purpose of putting the system in difficulty leading it to crash. The load test, on the other hand, is performed under normal conditions and has the purpose of verifying the stability and speed of sending responses out of extreme and deliberately difficult conditions.

How to keep values ​​under control?

To constantly monitor the resources used, you can rely on our service active monitoring which analyzes the status of an application on your server or device in real time. Just activate the probes on the resources you want to check including CPU load, RAM usage, available storage space and so on.

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