The Voucherify Java SDK by Rspective offers a coupon / voucher platform that can be integrated to existing Java applications. The current version requires Java 6+. Use cases: promo codes, loyalty coupons, vouchers and gifts, mobile apps
Roomorama is not the only one in the person to person travel accomodations game. The company is in a space that’s been well established by other players: CouchSurfing, Vacation Rentals By Owner and, of course, AirBnB. While there's an AirBNB API planned, the only room rental site that is currently public with its platform is the the Roomorama API.