Hello @daliang,

Thank you for posting here in the Community. Let's get you over to the support you need about API.

I can refer you to the department that can help you with app integrations. We have a separate forum called Intuit Developers, where you can find engineers who can suggest an API that you can use with QuickBooks. Here's the link: Intuit Developers Community.

Supports and users from the website assists with third-party app integrations, take part in software developments and other tools for QuickBooks.

For additional reference, I've also attached an article you can use to manage app subscriptions in QuickBooks: Disconnect an app and change subscription.
 
Please know that I'm just a post away if you have any other questions related to QuickBooks. Take care.