Hardware you plan on running on?
"send data" how big are the records?
Best to just setup a test sending a few hundred and see how it goes.
This question has been asked allot. try searching for it.
https://discourse.nodered.org/t/performance-scalability-and-security-evaluation/38049
https://discourse.nodered.org/t/node-red-scalability/15938/2
https://discourse.nodered.org/t/using-node-red-for-enterprise-software/40247/9
I feel this question is allot like big data.
"Big data is like teenage sex: everyone talks about it, nobody really knows how to do it, everyone thinks everyone else is doing it, so everyone claims they are doing it...." (Dan Ariely)