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.

Gumroad - An all-in-one solution to sell your work and grow your audience.

Chargebee - Chargebee lets you manage subscriptions and payments at scale, handle custom recurring billing scenarios, reduce subscription churn and simplify accounting.

Easy Digital Downloads - Easy Digital Downloads is a complete eCommerce solution for WordPress.

Killbill - Open-Source Subscription Billing and Payment Platform

Ko-fi - Ko-fi offers a friendly way for content creators to get paid for their work.