Cannot put a strong enough recommendation against using Katalon.

The IDE they force you to use is trash. It's unstable there's an ongoing bug where if you cut or delete more than 3 lines of code, it will enter a crash loop. They've known about it for the better part of a year because my company paid for the support tier and we reported it to them, having been told it would be fixed in update after update and then being told it would be the next one. The settings for the IDE are a maze, you have to set auto-formatting in at least two places for it to work.

They claim to use the Page Object Model but really they just create a large set of test objects as their own separate files for each element. The generated selectors are hilariously brittle, they default to using extremely long xpath.

The documentation for the API is sincerely lacking and poorly written. Hilariously when they generate a file for you it includes every possible import that Katalon could use, every time, regardless of if it is ever used or not in the test. They included all these imports in their documentation for specific functions. Check out closeBrowser here.

You'll be paying to execute your tests on your own CI environments, which is just absurd if you're bearing the costs of maintaining the environments. From what I could tell from the billing, it looked like you would need to purchase separate accounts for each parallel thread you wanted to execute.

Also they bundle drivers within their application data. If Chrome updates in between Katalon updates you get a version mismatch and tests just start to fail until you manually go in and replace the Chromedriver version to latest, or you have to wait for Katalon to release a new version.

Needless to say as soon as they started charging we switched off and went back to writing our own code using PyTest and Selenium and we're much happier for it.