MailChimp WHMCS Integration is a module for WHMCS that enables you to automatically subscribe your clients in WHMCS to your MailChimp Mailing List. You can elect whether or not to offer Double Verification to your subscribers. When a user ceases to be your client in WHMCS they will be automatically removed from your mailing list. Your users can opt-out at any time from receiving further communication from within the client-area of WHMCS .