Tango Card — which brings together some 500 companies’ gift cards so that they can easily be used by companies like Microsoft, Chevron and Marketo to help build out their own schemes for gifting those cards to their employees, customers, or other businesses to in turn offer them to customers — has raised $35 million to expand its business... The space that Tango Card is working in is akin to what Stripe is doing in payments. All the hard work is behind the scenes and taps into something that companies want or need to do but often find difficult, costly or time consuming to sort out themselves. Tango irons out the work in the backend and presents an easy way of integrating it at the front end by way of an API.

https://techcrunch.com/2018/05/22/tango-card-raises-35m-for-its-rewards-as-a-service-gift-card-aggregation-platform/