Using Apple Developer as proof of sales between two companies We are currently negotiating with a company where that company will use our technology (image recognition) to create an iOS app. We will receive a Royalty based on sales and we do not know the company enough to feel that we can trust them. Neither me nor my co-workers at our start-up are Apple developers. 

We want to specify in our licensing-agreement that they should show us their sales via documents from their Apple Developer account. What are the possibilities / do you have any input on what kinds of documents we should specify? 

I give the three ideas I am thinking of so far:


Include us as receivers in apple-emails if they are generated on a monthly basis on sales.
Send us PDF from sales-reports from Apple.
Give us special login-password once a month to check.


Is there any better that I am not aware of?

All the best
Duran
The app developing company will publish on the App Store under an App Developer license from Apple. You can ask them to create an iTunes Connect account for your company under Sales role. Using it you get access to Sales, Trends and App Analytics.

For further details you can refer to the Apple Developer support documents, iTunes Connect Resources and Help and User Roles - iTunes Connect.