In their article, Why can't I use MailChimp to clean my list?, MailChimp (a leading ESP) recommends these third party services for validating and cleaning your list:
- http://www.briteverify.com/brite-pricing
- http://www.datavalidation.com/email-validation-pricing/
- http://www.leadspend.com/mailchimp-promo
Some Email-marketing Service Providers (ESPs) offer features to filter out known-bad-addresses, but ultimately the responsibility falls on the list manager. The most reliable way to validate an email address is by a two-step question and response: first, an email address is entered during sign-up; second, an email is sent to the submitted address requesting confirmation; third, the recipient clicks a link confirming their subscription. This ensures that the email address is technically capable of receiving emails and that the intended recipient has access to that email account. In traditional email marketing, this process takes place during the initial account creation or subscription process and is commonly referred to as "double opt-in".