It's not clear in the documentation whether I have to use my own server in conjunction with the App Store for in app purchases for auto renewable subscriptions.
Is it possible to use auto-renewable subscription in app purchase without my own server?
Some info like the subscription expiration date can only be retrieved by validating the receipt with Apple. You can validate with Apple right from your app (which isn't recommended by Apple). You can also use a receipt validation service like Fovea.Billing which provides a REST API doing the receipt processing for you.