What would be the best way to safely use secret API keys so they can be used in the Katalon WEB scripts (not API scripts) on Jenkins (with Katalon plugin) nodes that are used on demand?

What would be the best way to safely use secret API keys (needed to work with the Twilio API written in Java) so they can be used in the Katalon WEB scripts (not API scripts) that are to be run on Jenkins (with Katalon plugin) nodes that are used on demand?