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.
Lago Billing - Open-source alternative to Stripe Billing and Chargebee
TypingDNA Authenticator - 2FA codes in your browser, secured by the way you type
Metronome - Metronome helps software companies launch, iterate, and scale their usage-based business models, with billing infrastructure that works at any size and stage.
Stripe Billing - A set of tools for billing and subscriptions
Zuora - Zuora creates cloud-based software on a subscription basis that enables any company in any industry to successfully launch, manage, and transform into a subscription business.