MailMonitor works by sending test emails to a network of seed accounts across various Internet Service Providers (ISPs) and email clients. It then tracks the delivery and placement of these emails, providing you with a comprehensive report on their performance. This includes information on whether the emails landed in the inbox, spam folder, or were never delivered. Additionally, MailMonitor can provide insights into the causes of any deliverability issues, such as blacklisting or poor sender reputation.