Some more data: Apple will keep 30% of every transaction inside the app; users buy the virtual coins with real currency to us. They spend the virtual coins inside the app in exchange for answers given by other users, WHO receive coins. These latter users can then cash out the virtual coins. Does Apple allow such a structure in its store?
Hi guys, straight to the point: is it possible to have an app where one user can pay virtual coins to another user in exchange for answers to questions, whereas the virtual coins can be converted into real currency and cashed out?
You're creating/facilitating a 'virtual currency'.
At the very least, IAP can't be part of your scheme, so no, Apple wouldn't get a percentage, and my opinion is that you'd need to purchase/redeem outside the app, completely.
Since there seem to be several points in section 11 of the review guidelines that might be of importance to you, I'll link to them and let you decide:
https://developer.apple.com/app-store/review/guidelines/#purchasing-currencies
Also, pls. resist using the title as your question space, thanks.
First, 'no' to the redemption:
11.4 Apps that use IAP to purchase credits or other currencies must consume those credits within the App
Second, arguably 'no' to the use of virtual coins in exchange for "answers":
11.3 Apps using IAP to purchase physical goods or goods and services used outside of the App will be rejected
Third, perhaps you can do this all outside of IAP (using a third party payer like PayPal) as long as the services are perceived to be delivered not as part of the app - it's complicated.