When comparing Katalon Studio vs PhantomJS, the Slant community recommends PhantomJS for most people. In the question“What are the best headless browsers for testing?” PhantomJS is ranked 1st while Katalon Studio is ranked 7th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Valuable Features
Pro CI tools
CI tools available for e.g. Jenkins and Teamcity.
Pro SOAP and REST
Supports both SOAP and REST testing.
Pro Supports screen capture
Pro Used in many open source projects
Pro Supports many browser standards
PhantomJS has full DOM and CSS parsing, JSON, canvas, and SVG support.
Pro Built on WebKit
WebKit is becoming the gold standard for browser compatibility, making it a good starting point for native headless browser testing.
Cons
Con Does not support nested shadow root DOM structure
Con Not for desktop applications
Currently Katalon Studio supports Web, Mobile, and API automation testing.
Con Heavy file to download
Con No free version anymore
Despite promises made of "being free forever".
Con Slow sometimes
Con Deprecated by Puppeteer
PhantomJS is no longer actively maintained by the original authors. Puppeteer is said to be a replacement supported and backed by the Google Chrome team, now.
Con Heavy setup
You'll often end up having PhantomJS binaries connected via WebDriver to your testing framework, possibly using client/server especially if you want your test running with something else than Java. This means an overhead in terms of maintenance and performance, but still usually lighter than running a full browser (like Chrome, Firefox, IE).
Con Browser closes unexpectedly
It often happens when running on more then 5 (my measurement) JVM instances that the browser gets stuck and quits unexpectedly. This can be partially solved by running the instances one by one instead of parallel (this is a problem when testing Jenkins and Bamboo agents) but I don't believe this qualifies as a solution. The error is called UnreachableBrowserException
.
Con Elements are sometimes not visible
This is an error which occurs with almost no reason, PhantomJS sometimes decides that it cannot click the element even though the element is intractable or enabled.
This happens if you have to scroll to see the element (and these are not pages that load elements with JavaScript) which is strange because PhantomJS should catch the whole page if it is not loaded explicitly with JavaScript. This problem partially goes away with re-sizing the browser, but that does not really qualify as a solution.
The error it raises is: ElementNotVisibleException
.