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.
Giftbit Payment API - Stripe for gift cards
Giftbit - Buy, send and track digital gift cards for your reward and incentive programs.
Raise - The easiest way to save money on the go
Rybbon - Send digital e-gift cards as marketing incentives or rewards with Rybbon, which integrates with Marketo, HubSpot, SurveyMonkey, and Qualtrics.
Gemnote - Handwritten cards & premium custom gifts for companies