Best Referral Programs - A curated directory of startup referral programs
AffiliateWP - A powerful affiliate marketing solution for WordPress.
Weferral - Open source referral & affiliate management software
ReferralMagic - Turn your users and customers into referral magnets.
KickRef for KickEX - B2C version of a 10-level referral program with many perks
Echo - Golang HTTP server framework