ERP Backend Functionality Enhancement

I have an ERP prototype running at invora-erp.netlify.app and the next milestone is all about solid, reliable backend functionality. The current interface is mostly in place; what I need now is a structured, production-ready server side that can scale and plug cleanly into the existing front end... (Budget: ₹12500 - ₹37500 INR, Jobs: AngularJS, API Development, Backend Development, Django, Node.js, Python, RESTful, Software Architecture)