Hello, Greetings from Jay. I have ample amount of experience on xero api integration, xero app (with key/secret and public key certificate). Experience on creating different types of invoice (draft, awaiting payment, paid etc). Also hands on experience with invoice payment as well as generating credit note when invoice is refunded. I have knowledge of creating different types of invoice and testing it. More than that I can help you to choose xero bank details and tax codes for your invoice line items. I am very familiar with Accounts, Invoices, Payments, Contact/Customer, Organisation etc entities of xero. Also I have experience on synchronizing invoices not only in xero but also on myob, sage accounting application etc.