Matt Pliszka reviewedViral Loops for StartupsVirality for startups made easy 💪
 Recommended
Pros: 

pre-defined templates, real companies' case studies, easy to create customized referral campaigns

Cons: 

no free version, not the cheapest solution

One of the best referral marketing solutions out there to create viral campaigns for your startups.

Matt Pliszka has used this product for one month.