Viral Loops - Viral Loops is a viral and referral marketing platform to launch ranking competitions, sweepstakes, pre-launch and referral programs.
Best Referral Programs - A curated directory of startup referral programs
Waitlist API - Quick and easy waitlist with built in referral.
Troopl - Connecting people and companies via the magic of referrals
Referral HQ - Get referrals at Google, Facebook, and other top companies!
Proof by SparkLoop - Display your newsletter stats on your website for free.