Proofy - Quickly validate and verify your email lists.
Nudgify - Nudgify is a Social Proof App that includes FOMO, Urgency and Review Nudges. Adding Social Proof notifications to your site helps you build trust and increase conversions on Shopify, Wordpress or any other platform.
Trumail - Free email verification API
NotificationX - Best social proof and FOMO marketing solution for WordPress to increase conversion rates.
Email List Verify - The Fastest Way to Improve Email List Deliverability and ROI
ProofGain - Supercharge your conversions with a simple social proof tool