If you are more productive using Node.js for back-end and React/other JS framework for front-end then don't worry about it and go ahead. Especially so for a sma

If you are more productive using Node.js for back-end and React/other JS framework for front-end then don't worry about it and go ahead. Especially so for a small business with few development resources. The performance issues can be tackled when they arise and in in some areas you could use addons or even just break down some work into another service/micro service using Java or whatever. The productivity benefits can be massive and that's usually the bigger issue if you're creating a general web/service. I work on tesults.com and it's all JS.