Do Wix, SquareSpace, Etc Support API Calls and Repeat Regions?

I have a client who wants to re-build their web site in a modern wysiwig environment and then access information about different events via an API call to my app.

So I’m wondering if the likes of Squarespace or Wix support external API calls and repeat regions in the way that Wappler does…

Do you have any experience of this?