Verify email addresses before you send: single, batch (50) and bulk lists (10,000).
Free
One server, in email. Verify email addresses before you send: single, batch (50) and bulk lists (10,000).
Verify email addresses before you send: single, batch (50) and bulk lists (10,000).
The rest either hold an API key issued by the publisher or ask for nothing.
Listed without a verification tick. Read the listing before installing.