RevenueCat - In-app subscriptions made easy
Revenue Reporting from Drift - Let's end the war between marketing and sales.
RevenueStory - Subscription analytics built on top of your billing system
Stripe Revenue Recognition - Stripe Revenue Recognition simplifies accrual accounting so you can close your books quickly and accurately.
Apple - Available on iOS
Baremetrics Cancellation Insights - Cancellation feedback w/ revenue reports & automated emails