ZeroBounce - Removes invalid emails from your list to prevent email bounces from ruining your deliverability.
Email List Verify - The Fastest Way to Improve Email List Deliverability and ROI
Email Checker - Email Checker offers a real-time API and bulk validation for list cleaning.
NeverBounce - Real-time email verification and cleaning to ensure emails never bounce.
Bulk Email Checker - Bulk Email Checker is an online service used to Verify and Clean Email Addresses. Its Easy to Use, Reliable and used by 1000's of Businesses.
Email Verifier - Email verifier app lets you verify email.