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

Tango Card - Tango Card bundles an awesome catalog of e-gift cards and other e-rewards with easy-to-use technology and expert program support.

Recurly - Subscription billing and recurring billing management. Recurly offers enterprise-class subscription billing for thousands of companies worldwide.

Tremendous - Tremendous is a customer and employee loyalty platform that allows companies to reward their customers for surveys promotions and referrals.

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.

Rybbon - Send digital e-gift cards as marketing incentives or rewards with Rybbon, which integrates with Marketo, HubSpot, SurveyMonkey, and Qualtrics.