Your question is Isolating Bugs in Multi-Party Integrations. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
What is your approach to isolating a bug in a multi-party integration where the issue could lie within either Intuit's API or the partner's proprietary software?
Explain how you would establish the failing boundary, collect evidence without access to the partner's source code, and distinguish an Intuit defect from an integration, authentication, serialization, or retry problem. Address how you would reproduce the issue, compare expected and actual HTTP behavior, and communicate the finding to both parties.
Scope: Discuss REST integrations such as the QuickBooks Online API, OAuth 2.0 authentication, HTTP diagnostics, logging, and testing practices.