How to disable service workers in Safari 12.1? (Mac) In Safari 12.1 Service workers can’t be disabled anymore via Develop > Experimental Features. I guess it’s not an experimental feature anymore. 

Is there any other way to disable them? Sometimes the whatsapp service worker seems to have a hiccup and uses 100% cpu utilization. 

earlier solution for safari versions pre 12.1:
How to disable service workers in Safari?
You can try to turn off the feature via the Debug menu.  For me, using Safari 12.1.1, It is listed under

Debug -> WebKit Internal Features -> Service Workers

Note that I am referring to the internal Debug menu, and not the Developer menu.  The Debug menu is activated by writing the key IncludeInternalDebugMenu  into Safari preferences (e.g. defaults write com.apple.Safari IncludeInternalDebugMenu 1 -- under Mojave, you will have to grant Full Disk Access to Terminal.app first; otherwise the setting will not take.)

I'm not sure if this persists across browser restarts, though.