Stripe - Online payment processing for internet businesses. Stripe is a suite of payment APIs that powers commerce for online businesses of all sizes. Use Stripe’s payment platform to accept and process payments online for easy-to-use commerce solutions.
POINT - Awesome link sharing/commenting with friends.
Rocket Money - Find your paid subscriptions and cancel with one click
microChange - Snapchat-Venmo hybrid for donating.
Chargebee - Chargebee lets you manage subscriptions and payments at scale, handle custom recurring billing scenarios, reduce subscription churn and simplify accounting.
The Groundwork - The API for building modern movements