"Gateway" is a generic term and may refer to various tools or services related to gateways. Additional context is needed for a specific description.
MailChimp is all-in-one e-mail marketing platform that fits everything you need to know about your subscribers into one neat and organized place. Its powerful features and embeddable sign up forms help you build an engaged audience you can communicate with easily anywhere and anytime.
MailChimp Integrations