An ESP is an Email Service Provider. An ESP is a business solution that hosts email services and software on independent servers. ESP empower other businesses to send email campaigns to their email subscribers.
Using an email service provider is a low-cost and relatively unobtrusive way to reach your audience with a variety of marketing content. The most common types of marketing campaigns sent via email service providers include transactional updates, weekly newsletters, and seasonal promotions, all designed to keep your brand top-of-inbox and top-of-mind.