Hi paytocompanytest,
Thanks for posting in the Community!
To be able to integrate your payment application with QuickBooks Online, I would recommend contacting our Intuit Developers through: https://developers.intuit.com/app/developer/homepage and click on Help. Our developers can provide more information on how to integrate the application to QBO.
Furthermore, our product team is in the process of working out with our banking engineers and partnered financial institutions to be able to get Open banking connection in the future. We remain committed to providing the best possible bank feed experience for all QuickBooks users and this includes delivering Open Banking in future, which will enable service enhancements and resolution to issues such as this.
Post again in the Community if you have further concerns. I'll be around to help you.