re: So, my original topic was marked spam because someone posted some sh*tty comments there. But the question remains unanswered.
Hi! I would like to know if I can connect to Smart Things with any tankless water heaters from this guide and regulate the temp and schedule the re-circulation pump?
I’d really appreciate it if you recommended something cheaper 
Sorry about deleting your original post that may have been an error on my part (as you notice) it got caught up in the mess because of your link.
You can develop a SmartApp either to integrate a cloud-connected device into SmartThings Cloud, or to create an Automation.
A SmartApp can be an AWS Lambda function or a WebHook endpoint.
Read more on SmartThings HERE
Ron
Samsung Developer Program
It’s ok. The whole thread became a mess when spammers started posting their spam. I’d probably do the same.
Now, this is useful. Thank you very much!