Hello there, pwr0082523.
I know you want to enter a large number of estimates in QuickBooks Online. I can route you to the best support available to ensure you'll get the help you need.
QuickBooks is an accounting program that may be used to sync other business apps. If you've developed a certain platform to automate a business process, I'd recommend reaching out to our Intuit Developer's center. They'll be able to walk you through the QuickBooks API connectivity procedure.
To do so, either log in or create a new account by visiting our Intuit Developer's website and submit your questions from there. Once completed, someone from the developer's team will respond to any questions or issues you may have.
Also, for more information on how to use project features and how to integrate QuickBooks Online or QuickBooks Time, check out this handy article:
Let me know if you need further assistance with API. We're always here to help you.