What’s the difference between senders, ESPs, and MBPs?

Senders are organizations or individuals who create and initiate email campaigns. You're the sender. You decide what to send, to whom, and when. You bear responsibility for content, consent, and compliance.

Email Service Providers (ESPs) are platforms that help senders manage and transmit email. Mailchimp, Brevo, SendGrid, Smaily, and Klaviyo are ESPs. They provide sending infrastructure, list management, templates, analytics, and compliance tools. ESPs send on your behalf using their infrastructure.

Mailbox Providers (MBPs) receive and store email for recipients. Gmail, Microsoft Outlook, Yahoo Mail, and Apple iCloud are MBPs. They operate spam filters, organize inboxes, and decide whether your email reaches the inbox, spam folder, or gets rejected. MBPs serve recipients, not senders.