Filed under Load Testing, Performance Testing.

Standard deviation and percentiles are very helpful when comes to calculating the response times in a load test or a performance test.

Standard deviation is just like it sounds: the routine deviation around the average. Standard Deviation can then be used as a gauge of longer response times.

For normal distributions, we know that roughly 70% of the response times will be within one standard deviation of the average; and that about 95% of the responses will be within two standard deviations.

The standard deviation should be a low number, if your load test is consistent in load you want to see this number low because it means most response times are close in number.

If the Standard Deviation number is too low/high you can use it to identify a potential bottleneck in your web application or website.
The mean is the average, which can be pulled higher or lower by a cluster of extremely fast or slow responses being collected

The Median or the 50th Percentile is great but only accounts for what 50% of your users will experience. Would be better to check the 90th(95th) percentiles values, rather than mean, to ensure only those 10% wildcard calls are ‘missed’.
Typically, we’re only interested in the poor performers, so we pick a few top percentiles, like the 85th, 90th, 95th, and 99th.

Load testing is an iterative process. Once you find one issue, you need to re-run the load test and find the next! Here are some load testing tips on how to run your load test. has standard deviation, mean, median (50th percentile), 90th(99th) percentiles and minimum and maximum metrics to all load tests.

Filed under Page Load Time, Performance Testing, Website Speed Testing.

Today we are going to website speed test the landing pages of the most important car producers and sellers in the UK.


First tested site: UK website of Audi manufacturer

Screen Shot 2016-02-25 at 00.33.16

Next tested site: UK website of Vauxhall manufacturer

Screen Shot 2016-02-25 at 00.33.44


Next tested site: UK website of Ford manufacturer

Screen Shot 2016-02-25 at 00.34.08


Next tested site: UK website of Land Rover manufacturer

Screen Shot 2016-02-25 at 00.34.44


Next tested site: UK website of Mini manufacturer

Screen Shot 2016-02-25 at 00.35.07


Next tested site: UK website of Mercedes manufacturer

Screen Shot 2016-02-25 at 00.35.25


Next tested site: UK website of Toyota manufacturer

Screen Shot 2016-02-25 at 00.36.04


Last tested site: UK website of Honda manufacturer

Screen Shot 2016-02-25 at 00.36.28


In terms of page load time the order would be:

  1. Mercedes site – 865 ms
  2. Honda site – 2055 ms
  3. Vauxhall site – 2183 ms
  4. Audi site – 2420 ms
  5. Ford site – 2611 ms
  6. Mini site – 2649 ms
  7. Toyota site – 2821 ms
  8. Land Rover – 3959 ms

In terms of the performance score (the score given based on compression of different types of resources, caching …) the order would be:

  1. Vauxhall site – 68/100
  2. Honda site – 58/100
  3. Audi site – 55/100
  4. Ford site – 55/100
  5. Mini site – 52/100
  6. Land Rover – 41/100
  7. Toyota site – 31/100
  8. Mercedes site – 24/100


Seems that almost all of the sites have a lot ore to improve to achieve the score closer to 100. For this the section with the Advice from the LoadFocus platform gives a lot of hints on how to improve this. Improving the performance score will also improve the page load time of the pages measured.

The tests were run using the Website Speed Test functionality of the LoadFocus platform:


Enjoy. Make your sites perform better for your customers satisfaction.



Filed under Load Testing, Page Load Time, Website Speed Testing.

When do you need to load test or measure the loading time of your application on localhost:

  • before you deploy your application the first time and assign a public IP
  • during development of a new feature that you want to test in terms of performance metrics

Below are the steps that will help test your application on localhost:

  • Go to
  • Create an account
  • Download the ngrok software on your localhost
  • Install the auth token that you have been assigned when you created the account on
    Ex. ./ngrok authtoken 2CN4XNu97Hk2KCbuKF9pp_2NqX7j8kBntMBSEuG9mwv – change the last part with your auth token
  • Start ngrok on your localhost like:
    Ex. ./ngrok http 80 – this will forward the requests to port 80 on your localhost (in case you need another port just change 80 to the desired port)
  • Once started in the command line you will see the url that you need to use in your load test (should be something like the following:
  • Log into your LoadFocus account and create your first test
  • Set Test name, the location from which you want to run the test and the url which in this case will be something like:
Screen Shot 2016-02-24 at 20.15.14

That’s all. Enjoy.

P.S.: Ngrok software will have an impact on the results of the test but is a good starting point until you will deploy your application on the production environment. is a Cloud Testing Platform used for Load and Performance Testing for Websites and APIs and Website Speed Testing with Analytics.

Filed under Integrations, Load Testing, Performance Testing, Test Automation.

We’ve released our load testing plugin for Jenkins CI.

Use the Post build actions and define your load test limits in order to mark the build UNSTABlE or FAILED

Easy multiple accounts access via the credential Jenkins plugin.

More details here:

Installation Steps:
1. Create your load testing account on
2. Copy your API key from
3. Go to Jenkins Dashboard and click go to Manage Jenkins > Manage Plugins > Available
4. Locate and install LoadFocus Load Test plugin
5. Go to Manage Jenkins > Manage Credentials and add your API key to the stored credentials

Schedule your tests inside Jenkins to monitor failures and application bottlenecks.


Results are present in the job’s result for each run:

LoadFocus-list-results LoadFocus-result-details

Happy Load Testing!

Filed under Load Testing, Performance Testing, RESTful APIs, UI Testing.

We’ve implemented the Header Presets functionality in order to save time and reused same set of headers for future load tests.

The steps on how to use the Header Presets are described below:

  • Under the URL section click on the Headers button
  • Click “Manage Presets” button and Popup appears with the list of current presets (empty at the beginning)
  • Click “Add” button to add new presets
  •  New Presets popup appears
    • Select a name for the current set of headers presets
    • Start adding key/value pairs for the current preset
    • Click “Submit” when finished adding all the key/value pairs


  • The new preset will be visible in the Manage Presets popup
  • If you want to edit the current preset, just click on the preset name and edit the preset (names and values)
  • Close the “Manage Presets” popup and the presets dropdown will be populated with all created presets
  • Now just select the desired preset and the Headers will get populated with the values from the preset
  • You can click on any preset in the dropdown, the values will append to the existing ones

Use the headers for load testing websites or APIs with custom headers.

Hope this helps is making LoadFocus a better and easier load testing service and your choice for the load testing tool to use. is a Cloud Testing Platform used for Load and Performance Testing for Websites and APIs and Website Speed Testing with Analytics.

Filed under Chrome Extension, Integrations, Load Testing.

Extension Provides Capability to Run Load Tests and View Results Directly from Your Browser

LoadFocus today announced the release of its Google Chrome extension as the newest addition to their load testing platform for developers. LoadFocus’s Chrome extension allows users to run load tests directly from their browser without the need for any additional software. Load tests results are displayed inside the extension, with the ability to view complete results and charts with a single click.

Using basic metrics like response time, latency, hits per second and total errors, users can easily view the performance of their websites and compare with previous results, easily from the load testing chrome extension.

No need to install anything to run performance test, the Chrome extension will create everything for you automatically.

Get the LoadFocus Chrome extension is free to use for all plans.


load testing chrome extension

Filed under Load Testing, Performance Testing.

We created a list with top reasons why load testing should matter to your website or APIs:

  1. to identify potential bottlenecks of your application
  2. to discover the number of concurrent users that can access your application without a heavy degradation of the user experience
  3. to find out the breaking points of the technology stack used by your application
  4. to find your application’s behaviour under load
  5. to check the time it takes for your server to respond to clients and understand if your website loads in a decent amount of time
  6. to find out how slow the APIs or any other web service respond under heavy load
  7. to understand if the database technology or the connections to the databases (Postgres, Redis, Mongo etc) represent a bottleneck in your application
  8. to find out if the changes done in each release had a bad influence on the performance behaviour of the application
  9. for overall changes that are likely to influence the performance behaviour
  10. for fine tuning the different technology stack components
  11. to discover hardware issues or hardware/VM related problems, like limitation on the number of threads or file descriptors configured on the system
  12. if your article reaches the first page on Hacker News, but your website is down you regret you haven’t considered load testing previously
  13. to know how many parallel users your website can handle
  14. to understand if any errors appear to the end users and how are these going to affect their journey
  15. to be confident you can make a email campaign and all your customers are going to experience the designed workflow is a Cloud Testing Platform used for Load and Performance Testing for Websites and APIs and Website Speed Testing with Analytics.