I imagine I'll get downvoted for participating in the language flame wars but....
I've been working on a NodeJS backend at my main gig for the last two years.
For two years before that I was working on an backend application written in C#.
Based on my experience with those two systems, the answer to the question "When should I use Node for the back end?" should be: Only if your main language is javascript and you don't have the time and/or inclination to learn something else.
For me, working with C# was massively more productive. Static typing, robust async/await, and the fantastic tooling you get with Visual Studio + Resharper are huge benefits. Dynamic typing, callbacks and/or weird promise logic, and dodgy open source libraries which may not be very well documented or maintained are huge downsides for Node JS.
I would never choose to write a new project's backend in Node JS.
YMMV.
I've been working on a NodeJS backend at my main gig for the last two years.
For two years before that I was working on an backend application written in C#.
Based on my experience with those two systems, the answer to the question "When should I use Node for the back end?" should be: Only if your main language is javascript and you don't have the time and/or inclination to learn something else.
For me, working with C# was massively more productive. Static typing, robust async/await, and the fantastic tooling you get with Visual Studio + Resharper are huge benefits. Dynamic typing, callbacks and/or weird promise logic, and dodgy open source libraries which may not be very well documented or maintained are huge downsides for Node JS.
I would never choose to write a new project's backend in Node JS.
YMMV.