If you own a product, send a newsletter, or handle users like I do for myself and my clients, you would know that email verification is an integral part of managing emails. The Email Verification API by WhoIsXMLAPI is a solid email validation API which makes use of an extensive WhoIs database combined with smart algorithms to validate the email addresses. It checks the given email address against multiple layers to verify it. Also, it fights the spam and disposable email addresses as well.