Load Testing Using loadUI – A Free and Open Source Load Testing Tool

What is loadUI?
LoadUI is a free and open source load testing tool that allows you to do complex load tests and test the performance by simply dragging the different components around. LoadUI lets you to create and update test cases while you run them. What is making loadUI powerful is the focus on usability through its visual interface and intuitive design combined with the flexibility that comes from the possibility of making changes during the test.

How loadUI works:

LoadUI consist of building blocks called Components that you drag from the Component Toolbar to the Project you’re working on. These components connect to each other by wires and there is no limit for how many components that you can create and connect.

What is loadUI

This way of drag-and-drop testing is especially useful during the test, since you can do complex load tests. The overview that you get makes it easier to try different combinations during the actual test and react to them immediately. In loadUI, Instant feedback is king.

Creating load tests in loadUI:

In order to run a test in loadUI you need at least two components (and an empty Project to work in);

– A generator
Which creates load, for example 100 requests per second.
– A Runner
That runs a certain type of test, for example a web test.

So let’s do it; drag out a Fixed Rate Generator and a Web Page Runner.
You can’t run them yet though first you need to connect them. You do this by connecting the nodes, or terminals, located above and below the components to each other with connections.

LoadUI components

So now connect the Fixed Rate Generator to the Web Page Runner.

Now that everything is connected you should enter what website you want to load test into the Web Page Runner. Your test is now ready to run! Click the play button in the top menu to make your generator start sending requests to your site.

You can now follow, in real-time, how the test is going by clicking the Results Workbench button. Once there, double click on your Current Run and, from the left hand menu, drag out Response Time to the rack.

LoadUI result


Congratulations! You have now created your first load test in loadUI. Play around with the widgets you have on your dashboard, experiment by adding some more, and try tracking other values in the Results Workbench. A good next step would to add an Assertion component and connecting it to the Web Page Runner. Then you can, for example, test how many times you your requests come through while following certain rules you set up (like taking less than 10 milliseconds).

Pro Tips:

Let a manager test!
This is the modern way of gorilla testing.  Let someone less proficient do the testing for you and see what breaks your service. It will also create an understanding and passion for testing within the management. A usual comment is “This is fun! But hard…”

It’s interactive, use it!
LoadUI is highly interactive and configurable in real-time, so take advantage of that.

Create a second test in real time against the same server with a different Generator and see if the system shows weaknesses when exposes to chaotic, life-like, behavior. Change this in real time and experiment.

Record your tests
Since loadUI is so interactive, reproducing the tests can be difficult. Use a screen recorder like Wink (which is free) to be able to replay your tests and see what caused the service to crash.

Work structured
LoadUI has support for test cases. Break up your tests into smaller test cases; you can always start them all at once.

Don’t double-work
If you have created functional tests in soapUI, you can simply run these in loadUI with the soapUI component. This way you don’t have to redefine the test another time in loadUI.

Write your own component
LoadUI is not only free; it’s open-source, too. That means that you can write your own components, in Groovy, if you wish. Only you set the limits for what is possible in LoadUI! Read more about creating your own components here.

Read more about loadUI, and download it here: Latest loadUI version

This is a guest article by Henrik Olsson.
About Author:
Henrik is a software developer for loadUI from Stockholm, Sweden with an academic background in Distributed Systems and a passion for usability. He is experienced in teaching and thinks that most things can be easily explained, if well modeled and accurately targeted.

Editor’s Note:
I’m glad to share this open source load testing tool with my readers. LoadUI and soapUI are the best open source software testing tools from trusted company eviware (now SmartBear). If you are thinking to introduce load testing tool on your project try loadUI and soapUI (functional testing tool).  Also I personally used soapUI  for many projects and will soon cover it in a separate article. I love the power and beauty of these open source tools!

If you used this tool and have some tips to share, please do it in below comment section. Also we would be happy to hear and answer your queries on loadUI.

Recommended reading


#1 Kirti M

me too used SOAPUI tool for api testing and it’s very powerful and easy to use tool.

I will try loadui. thanks for the info.

#2 Tej G.K


I’m new to this forum and need some help in gathering some notes on concepts of DBMS.
So kindly let me know the link from where i can download it.

Infact its simple ppl jus google it and download it and when it comes for the best study material from the depth of subject point of view. It becomes very diff.

Thank you in advance.

#3 Pratap Gusain

i have read documentation of these software. Its easy one to use , but it will more easy to use if you can upload a video tutorial of Load UI.

thanx for sharing such a nice tool !

loved it

#4 Partap Singh

Hi Writer

I have a question !

I want to know that if a site having a login page i.e. User

Name and Password , then how can we test that Login

Page ?

#5 Henrik Olsson


That’s a very good idea actually. I hope that we’ll be able to upload some videos not too far in the future :)


That depends on which authentication method you use.

If you are using HTTP’s Basic or Digest authentication, you can set the credentials in the settings dialog for the Web Page Runner (refer to http://loadui.org/Runners/web-page-runner-component.html#2-2-authentication).

If you are using anything else, like NTLM, WSS or something custom — you should use a soapUI Runner, making loadUI using the authentication that you set up in your soapUI project (refer to http://www.soapui.org/SOAP-and-WSDL/authenticating-soap-requests.html).

#6 Pratap

@ Henrik Olsson

well this is amazing..i couldn’t believe that how a open source tool may have such a rich functionality ?

this tool is really awesome!

Thanks Henrik :)

#7 Kiran

really helpful tool. i tried many tools and most open source tools lack some functionality but this seems good option both for tool UI and functionality.

#8 Ijaz


While creating a test it is very user friendly, can you plz help me while understanding the results area like how can I figure out whts the status of my site

#9 Fatima

Guys, Is there anyone who had done #Rational Manual or performance Tester?? I need your help!!!

#10 shoaib

Hi, its a really a very user frndly and superb in functionality But i jst want to know more about how to use it and how to analyse it i already visited to loadui tutorial but still some option in components are not clear to me, so plz tell me how to use it efficiently by which i impress to my team leader..

thank u in advance

#11 Alex

Good article

#12 tester

Good day,

I wanna now if i can record the steps executed in a web browser, i mean like a proxy?

#13 viknesh

wonderfull tool used for testing chat module in mobile application. lots powerfull feature to use in it….
very intersting tool… GUI were excelent in both soap and load….

#14 UmeshSG

Hi Henrik,
Seems to be very interesting Tool.. Can we load test the Chat Client Server(Linux) ?

#15 abrar tararr

Hi all…
i m doing manual testing of web applications in a pvt company for 2,3 months. Unfortunately i have no senior to guide me…
I need some practical test scenarios & Test cases (for guidance purpose.i.e. how to write test cases).
would any of you like to help me? plzz send me some test cases on the following id…i’ll be vry thankful…

#16 arlene

hi, can anyone pls help me hoe to test banking domain like,loan,stock,mutual fund,fixed income, option and real state portfolio? pls. email me jamoraarleneantonette@yahoo.com

#17 Pulu

How to download full version of LoadUi installer from below link


Whenever I have downloaded, I got only less than 1 mb size instaed of 113.8 mb. Help. Can anyone tell me another site where I can download the full version.



#18 Nagesh

How to Write function for right click

#19 Nilesh


If we got 80 soapUI test cases, can we run performance test at one go for all on LoadUI or do we need to create performance test of each soapUI test case on LoadUI and run them one by one?

Quick response appreciated.


#20 Jey

Nice Article.

Is is possible to use this Load UI for
Desktop and
Client Server applications?


#21 Subha


I’m new to testing. Now i have to do performance testing. which tool (open source)i can choose.

May i know how many companies using this LoadUI tool.
And how reliable that the tool is??

Please help me.


#22 Subha

And also, is that possible to test the authenticated urls????

Waiting for the reply.. pls help

#23 maedeh

is loadui work offline?please answer to me

#24 Sherin Jemima

Is SOAPUI a functional Testing Tool?

#25 Sherin Jemima

What is the Virtual user limit in LOADUI Open source tool?

#26 Pepa

It is a pity LoadUi is no more freeware and I could not find version 2.6.x anywhere on the web. Current 2.8.x and next on versions shall be trial only with time limitations.

Does anyone know where to download loadui freeware?

#27 Ankur


i wanna know that if i have to performance test my application on 100 users, so in that case should i need 100 different ids and password or is their any other way to perform same please clearify me for the same

#28 TT

Hi Henrik,

On the LoadUI NG Pro side I am aware that there can be multiple scenarios each with its own target and all of them can be run at the same time but is it possible for one scenario to launch multiple threads with different endpoints? Let me know if my question is not clear enough and i can send in my detailed question to your mail id. Hoping to get some solution.

Thanks in advance !

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