Hi Martin. I can only comment on the Shelly Pro 3EM which is the power meter for my heat pump. It has a very powerful scripting capability (subset of Javascript) which could easily send power data every 5s to any external server. I’m using this to send power data to my EmonCMS instance using an http get call with a URL I’m constructing in the script. You could just provide the script with your api key or whatever authentication you’re using for your customer to paste into a script on the Shelly. This works on all their Gen2 stuff. I’m generally a big fan of Shelly, especially since they don’t require their cloud to work.