I tried to manually install npm install --global node-red-contrib-blynk-iot in the /mnt/dietpi_userdata/node-red folder as the node is still in beta and there is no easy install version.
After a reboot and checking the node-modules folder and node red nothing shows up.
On this Github page where I got the npm from it doesn't actually say where it just says "If you installed Node Red globally use this command to install npm install --global node-red-contrib-blynk-iot"
And as I'm running a RPi with DietPi I followed the advice from a post here on the discourse, which states as above to install in /mnt/dietpi_userdata/node-red. which I did and there is no trace of anything having been installed.
Sorry I never start it in a terminal window, node red is one of the many software packages that DietPi's system can install and autostart's after a reboot, update etc.
Well, as I said, if you want to manually install nodes then you must do it from that folder, and it is the node_modules folder in there that will find them. Then restart node red and refresh the browser page.
There could be more than one node-red folder. When I said in my first post that you must install from the folder where the flows file is then you could just have said that you have done that.
I have just noticed that you used --global when when you installed the node. That means that it will not be in that node_modules folder, but in the global npm folder.
I see that in the readme for the node it says
Warning: FOR TESTING ONLY
This library is in beta, it is not stable yet!!
Do not use for production
I also note that it has been in that state for 18 months without any updates. Are you sure that you do want to use that node? If you do then I suggest you add an issue to the node's page on github and see if the author responds.
You used --global to install it which isn't a good choice for node-red node packages. If you want to install manually:
cd ~/.node-red // or wherever you have configured your userDir to be
npm install node-red-contrib-blynk-iot
If something you want to test isn't yet published to npmjs.org, you can install direct from github. with npm install gablau/node-red-contrib-blynk-iot.
Node-RED uses Node.js as its underlying platform along with the standard npm package manager, Might be worth you doing some reading on how node.js and npm work.
If anyone finds this topic because they were looking for assistance on installing node-red-contrib-blynk-iot, or wondering whether to use it because it's marked as being a Beta release and hasn't been updated recently, then @Ianszh's topic on the Blynk community forum, and the links contained in that topic might be useful...
Also, the Blynk Legacy servers have now been decommissioned, so if you previously used the node-red-contrib-blynk-ws with the cloud servers then this now has no endpoint to connect to.
If you're still running a Blynk Legacy local server then you'll still need to continue using the old node-red-contrib-blynk-ws