Leanplum

Leanplum (acquired by CleverTap) is a wildly powerful, deeply specialized titan that mathematically created the "A/B Testing and App UI Modification" sector. It doesn't just send push notifications; it mathematically alters the actual code of the app. It is the absolute weapon of choice for mobile product managers who want to A/B test a push notification *and* mathematically change the color of the "Buy" button inside the app simultaneously without waiting for an Apple App Store update approval.