Integration of Ecommerce with ERP

I'm planning to build an integration tool to connect E-commerce with ERP (Centralised HUB).

Easy for your reference

e.g) integrate Magento -> Netsuite

I have below doubts.

  • What are the technologies I need to use? (js framework,php framework...)
  • What is the right approach to sync data (direct databases sync, use api...)?
  • is immediate sync possible?
  • is there any free tool available to map the data(database field) between E-commerce to ERP?

Please advice me. Thanks.