Sales, gst/hst & vat software/ Web API

What the software needs to do? We will have to build a separate database where each item number is matched to a tax product code number from the taxability database (Database 1). If an item number cannot be found, we will have to use our default product code number. After matching the item to a tax product code, the API needs to use a taxability matrix (Database 2) to retrieve the cell where the ship to state and product code intersect. That will determine whether the item is taxable. I have the raw data for this, but you all have to build the database and this will have to be kept updated, so this should be something easily updatable. If the item is taxable in that state, the software will need to use a shipping address verification API to retrieve the Zipcode+4 (9 digit zipcode). With the nine digit zip code and address, the software will use that Geocode to connect to the sales tax rate API to pull the tax rate and add the sales tax to the shopping cart before checkout. If the Geocode cannot be found, the software should use the state, county, and city to find the maximum tax rate for that locale and return that tax rate. Tax-exempt organizations can elect to not be taxed and be required to enter their organization name, FEIN, and upload their tax exemption certificate. We will verify this information, and generate an internal tax exemption number. We will need to create a database to manage these exemption numbers and determine which ship-to states this entity is exempt from sales tax in. Technical Requirements: Developer Dashboard We need a dashboard where reports from the API can be developed, including error reports, log reports. We also need to be able to reset the live and testing APIs to an earlier version. We also need a live API and a training API; we also need to be able to generate a key for testing and production Events and Logs- we need a function that allows us to trace and check API activities in order to track issues and keep logs for system audits; the developer dashboard should contain the ability to retrieve events and logs. Technical/Software Required: Platforms : MS Windows Server 2016 or latest. MS SQL server 2017 for Database. MS. Net latest framework. Programming language : C# or vb.net The service should have two separated parts : Web API we recommend to get a simple (API Reference outlines) as a part of the proposal. Website or interface. More details will provided later. Please only contact if you are an expert. thanks.