NeverBounce - Real-time email verification and cleaning to ensure emails never bounce.
Email List Verify - The Fastest Way to Improve Email List Deliverability and ROI
Email Verifier - Email verifier app lets you verify email.
DeBounce - Email Validation, Email Checker, Data Enrichment and Appending Tool. Using DeBounce remove invalid, disposable, spam-trap, syntax and deactivated emails.
Verimail - Clean up email-address lists of any size or use our powerful API for real-time verification.
clearout.io - Clearout Email Finder & Email Verification Service - Drive sustainable business growth by expanding your reach, lowering hard bounces, and improving deliverability rates.