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:

1. Include us as receivers in apple-emails if they are generated on a monthly basis on sales.


2. Send us PDF from sales-reports from Apple.


3. Give us special login-password once a month to check.

Is there any better that I am not aware of?

All the best Duran