Referral HQ - Get referrals at Google, Facebook, and other top companies!
Feather Attribution - A free and tiny javascript library to track UTM tags, ref and referrer data client side so you can store these in your own database.
Referrer - Painlessly refer your friends for jobs
Voucherify - API-first Promotion Engine for promotions & loyalty.
Ladders Referral Hiring - Earn money by referring friends to your company’s open jobs
ReferralMagic - Turn your users and customers into referral magnets.