Node-red is flow based programming for Internet of Things. It's a very versatile development tool focused mainly on IoT. Because of the fact that it's like creating a puzzle, it is extremely user friendly. Apart from that, there are numerous addons and a great community. As you can see on github, Node-Red has a lot of contributors and numerous commits every week. The project is very helpful especially if you want to connect different devices or platforms.
On Node-Red you have flows that can either run on a physical machine or a docker container. You can run flows on SBC (like Raspberry Pi) or Arduino. Moreover you can run it on Amazon cloud, Microsoft Azure, Google Cloud, Alibaba Cloud or any other cloud infrastructure of your liking.