Email provider MailChimp has partnered with ReturnPath to offer a service where users can see how their campaigns will render in various email clients and get advance warning on any deliverability
issues.
Inbox Inspector offers horizontal and vertical preview panes, and "images off" mode, as this is often the default setting in most email readers and also includes a spam filter
check to ensure that no content in the body of the campaign or the subject line will trigger spam filters and undermine a campaign's deliverability. --Tanya Irwin