Based on our record, Email List Verify seems to be more popular. It has been mentiond 2 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
If you're not getting the right email addresses from ContactOut and it's bouncing back, you could always run the email addresses through something like emaillistverify.com to make sure they're valid before you try to email them. (you should do that always anyway to protect your email deliverability). Source: almost 2 years ago
Emaillistverify.com is the service I use. Source: almost 2 years ago
Checkmarx - The industry’s most comprehensive AppSec platform, Checkmarx One is fast, accurate, and accelerates your business.
NeverBounce - Real-time email verification and cleaning to ensure emails never bounce.
Appknox - Appknox is a cloud-based mobile app security solution to detect threats and vulnerabilities in the app.
ZeroBounce - Removes invalid emails from your list to prevent email bounces from ruining your deliverability.
GitLab - Create, review and deploy code together with GitLab open source git repo management software | GitLab
Email Verifier - Email verifier app lets you verify email.