Apility.io - Threat Intelligence Anti Abuse API to find out in advance if your users will be good customers. Learn if your users are on an abuse blacklist and decide how to proceed.
NeverBounce - Real-time email verification and cleaning to ensure emails never bounce.
TrueMail.io - TrueMail.io is an email checker service.
ZeroBounce - Removes invalid emails from your list to prevent email bounces from ruining your deliverability.
Simple Email Verifier - Simple email verifier is PHP script use Trumail API to verify bulk email addresses.
Kickbox - Verify your email address lists with our drag and drop interface, or integrate into your app with our API. Prevent fake and bot account sign-ups by confirming your users are real humans with a real email address.