[100.209.1.115] QuickBooks Enterprise to QB Online custom c# integration migration

Hello,

I am seeking some expert-level consulting to help migrate an existing Quickbooks Enterprise Integration to Quickbooks Online API. This integration is in charge of billing our customers and managing their accounts.

It includes:
Creating and syncing customers
processing payments
creating invoices
querying account balances

This will also entail setting up the authentication with Quickbooks Online.

All of the current projects should continue to work great as far as our integration with our systems. It just needs to be able to do all the same things to QBO as it did to QBE.

Here is our main method to help understand simplicity.
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///////////////////////////////////////////
//BILLING MAIN
///////////////////////////////////////////

qbcustomers.OpenSession();

//Migrate to QBO API
qbcustomers.processCreditMemos(creditMemos);
//Migrate to QBO API
qbcustomers.processPayments();
//Migrate to QBO API
invoices = qbcustomers.syncInvoiceCustomers(invoices);
//Migrate to QBO API
qbcustomers.processBalances();

authTrans.processTransactions();
//Migrate to QBO API
qbcustomers.processPayments();
qbcustomers.CloseSession();

///////////////////////////////////////////
// END BILLING MAIN
///////////////////////////////////////////

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Do you have direct experience writing against the QuickBooks API from C# in .NET 4.5.1 or like framework Console Applications?

Please list any certifications related to this project.

I am looking forward to your reply.