An email service provider (ESP) is a company that offers services to send, receive, and manage email communications. These providers typically offer features like email hosting, spam filtering, and user-friendly interfaces for managing inboxes. Popular examples of ESPs include Gmail, Yahoo Mail, and Outlook. Businesses often use ESPs to send newsletters, promotional emails, and other communications to their customers. Many ESPs provide tools for tracking email performance, such as open rates and click-through rates, helping organizations improve their email marketing strategies.