Integrating our web app with Navision 2013

Hi. One of our clients wants us to integrate our NodeJS web app with Navision 2013.

We’ve already integrated with cloud-based accounting systems like Xero using OAuth and REST, but Navision is clearly very different. Our web app is hosted on AWS while their Navision instance is local. We need to retrieve invoices, bank transactions, the chart of accounts, and company names.

We’re struggling to scope how hard this is, how long this would take, and how much it would cost to hire somebody if we decided to outsource. If anybody has any experience with this, we’d love to hear your advice.