Possibly.
But I think you are maybe asking how do you setup the inject node to send the variables?
Well, this is one way:
Then your URL in the http-request would be https://api.first.org/data/v1/countries?region={{region}}&limit.={{limit}}&pretty={{pretty}}
I hope you don't mind me saying, this is pretty base knowledge of Node-RED - perhaps investing an hour or so in some videos would help you help yourself?
I recommend watching this playlist: Node-RED Essentials. The videos are done by the developers of node-red. They're nice & short and to the point. You will understand a whole lot more in about 1 hour. A small investment for a lot of gain.
