Sahi vs. Selenium

Posted by | April 25, 2010 | Test automation | 16 Comments

Though Sahi is aimed at non-programmer testers and Selenium at programmers, we get a lot of queries on their differences. Here is a brief document which compares Selenium and Sahi.

To those who read this:
  1. If you are a Selenium fan, be open minded and verify the claims for yourself or contact us for clarification. And again, please be open minded. You may save a lot of time for yourself and your team.
  2. This document is biased towards Sahi because we built Sahi. We believe what we state is true, but if you have evidence to prove otherwise, please do contact us at
  3. When we say “Not sure” or “?” it means we do not have enough information because of lack of research on our part. Please verify for yourself.
  4. If you want a comparison between other tools and Sahi, we would be happy to discuss it.
  5. If you are another tool developer/supporter, please let us know how it compares and let the world benefit from alternatives.

Sahi vs. Selenium: Comparison document


Selenium Sahi
Works only on Firefox Works on all browsers (IE, FF, Chrome, Safari, Opera)
Has trouble recording IFrames, Frames and popup windows Can record on IFrames, Frames and popup windows
For Frames and IFrames, need to explicitly selectFrame Implicit smart identification of elements even across Frames and IFrames
Uses XPath for identification of elements if id or name not present Uses various algorithms to uniquely identify elements in a simple human recognizable way

Programming Language support

Selenium Sahi
Java, Ruby, Perl, Python, C# (and may be more). Sahi Script, Java, Ruby Sahi Script has the syntax of javascript but can interoperate with any Java code directly from script. The Java/Ruby drivers are available since Sahi V3
Needs language bridges for each new feature. For example, needs java bridge to invoke Flash via ExternalAPI. Sahi Script can directly invoke anything exposed by javascript.

Ease of use

Selenium Sahi
Easy to start with because of Selenium IDE which is a firefox plugin. Estimated start time less than 5 minutes More difficult than Selenium to start because it needs installation of Sahi. Estimated start time 10-30 minutes, depending on Java installation etc.
Deep learning curve when the need is felt to move from Selenium IDE to Selenium RC. There is only one mode of operation for Sahi. Extremely simple to learn and use for testers
Knowledge of programming language required Can achieve most automation with just functions and variables. Sahi has inbuilt APIs for most other complex tasks like data driven testing
Needs JUnit style of programming Can choose your own style
Uses XPath based identification for elements in complex html structures or those with dynamic ids. css selectors and javascript may also be used. Has nearness APIs like _in and _near which can help show nearness of elements. Eg. _image(“delete.gif”, _near(“username 4”))
Needs waits for making AJAX work No waits needed in 90% cases
Supports parallel execution Inbuilt parallel execution. Needs only one parameter change

Stability of scripts and ease of maintenance

Selenium Sahi
Smart DOM Relations resilient to UI changes No
Dependent on XPath
Difficult for testers to understand and debug
Does not use XPaths.
Uses _near and _in
Implicit waits for page load and AJAX:
1) Saves time
2) Keeps scripts simple
3) Reduces random failures
Explicit waits needed.
Ease of adoption by a team of testers Needs testers to know TestNG/Junit, XPaths, HTML structures, Frames IFrame knowledge, Javascript for AJAX conditional waits Sahi abstracts out all these for the tester.

Dependency on other tools

Selenium – Java (Others need something similar) Sahi
Needs JUnit (and optionally eclipse) to run tests No additional tools required. Tests run from the Sahi Controller/command line/ant
Non persistent reporting. Needs TestNG or something similar for that Persistent HTML reporting which can be shared via URL or file

Stability of product and number of releases

Selenium Sahi
Started 2004(?) in ThoughtWorks Started 2005 in ThoughtWorks
Version 1 took 5 years, Version 2 planned mid-2010. Moving away from original architecture to WebDriver based architecture Current release: Version 3 Number of stable releases in 2009: 7


Selenium Sahi
RC: 10.5 MB, Grid 15 MB less than 2 .5 MB with source
Not sure Runtime ~ 50MB for 3 parallel threads


Selenium Sahi
Needs external tools to create readable reports Inbuilt HTML reports with click through to relevant portion of script


Selenium Sahi
Build tool integration (ant, batch files) Yes Yes
Multiple OS support Yes Yes
Version Controllable Scripts/Code Yes Yes
HTTPS support/redirects Not sure Yes
401 Authentication, Windows/NTLM Authentication dialogs Not sure Yes
External proxy tunneling Yes Yes
In built APIs for data driven testing No Yes
Works only with browsers Yes Yes
Needs privileged modes on browsers for operation. (Privileged is bad) Yes No
Extensible on future browsers Depends on finding a way to use privileged mode on that browser Yes. Very little dependency on type of browser.
Editor support Has good editors in various languages Editor support for javascript is not as good as for Java.

Support available

Selenium Sahi
Free support via Forums Yes Yes
Paid support available Yes Yes
Authoritative training available ? Yes
Choosing the right web automation tool or web testing tool


  • felix says:

    How about stability?

    Even selenium scores badly against webdriver…

  • Hi Felix,
    Stability is something that comes up again and again. Thanks for bringing up that point.

    The cause for instability generally is due to
    1) Timeouts: when the server does not respond within time, the tests break. The tool should have the intelligence to wait for the necessary time. Sahi monitors page loads and AJAX and waits till activity has subsided. Selenium requires explicit waits or waits with conditions. The conditional wait is preferred but it complicates the script and demands more from the tester.
    2) Scripts very dependent on UI changes. In the absence of ids, Selenium is very dependent on XPaths, which is a hassle for testers. If the tester does not tweak the XPath, the tests will be brittle. Tweaking XPath for lots of UI elements is not a trivial task and can take up valuable tester time.

  • zawistol says:

    What would you recommend for Flex testing, we have a few folks using QTP with Flex add in.

  • Hi Lech,

    We are adding support for Flex too. It will follow the same principles of Sahi so it should be simple. If your requirement is urgent, you could check out FlexMonkey.


  • David Burns says:

    Selenium does use XPath but does not rely on it. Selenium has a number of different locator techniques from using IDs or Names to CSS or XPath. You can even use JavaScript if you wanted.

    Selenium, like Sahi, can invoke External APIs as long as you can access them via JavaScript. It something that is widely used by Developers/Testers around the world.

    Selenium 2 has implicit waits. Its something that Selenium has been lacking and was one of the things that we needed to do and have now done. Users can use the implicit wait but these will still timeout after a while because something not loading quickly can show a bug, its not that the test is brittle.

    Everything else looks correct from the Selenium point of view as far as I can see.

  • Hi David,

    Thanks for stopping by and sharing your knowledge. I have updated the post with your information.

    Selenium 2 is still in alpha so I am not adding in implicit waits yet 🙂


  • psylence says:

    Does Sahi handles subdomains while testing? As i understood, selenium does not..

  • Hi psylence,

    Yes Sahi works with subdomains. You may need to modify sahi/htdocs/spr/domainfix.js to set document.domain to the base domain.

  • psylence says:

    Raman, thanks for your answer!

    Btw, i have problems running Sahi on MacOS X. I've gooled and found this one: /forums/viewtopic.php?id=36 but it not helped(

    Maybe you can give some tips, thanks.

  • Hi psylence,

    If you post your problem on the Sahi Forums (/forums) or email us at, we will be able to guide you.

  • psylence says:

    Raman, thanks! I”m already managed to make it running finally.

  • halperinko says:

    Are there any plans for SAHI to support legacy Windows and/or Java applications not under a web browser?

  • Hi Halperinko,

    Thanks for the interest.

    Currently we are concentrating only on the web. We do not have plans for windows/Java apps right now.

    You could have a look at White for Windows Apps, Frankenstein for Swing apps and
    for SWT apps.


  • Dylon says:

    is Sahi using selenium at the back end ? what is the technology behind?

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