RevenueCat - In-app subscriptions made easy
Revenual - Aggregated sales reports for app makers 💵
RevenueStory - Subscription analytics built on top of your billing system
Baremetrics Cancellation Insights - Cancellation feedback w/ revenue reports & automated emails
Apple - Available on iOS
Stripe Revenue Recognition - Stripe Revenue Recognition simplifies accrual accounting so you can close your books quickly and accurately.