I love ocaml/reason and write a fair amount of code in both (both native and to javascript with bucklescript), but as a backend server the ocaml native ecosystem is far from ideal.
If I was asked to do a full stack project with reason today I would write node bindings and use them.
May I ask what your dev setup is? I've tried to get vscode + Reason language server working a few times (following the disparate sets of instructions on the site and Github repos) and was never successful.
I installed the Reason extension from Jared, I think, and started a new project.
My main problem was that I needed bs-platform installed globally AND locally in the repository. Otherwise the extension would display some errors that the bs-platform could not be found, which didn't help first, because I already installed it, haha.
If I was asked to do a full stack project with reason today I would write node bindings and use them.