Glossary/Email & Lifecycle/Email Service Provider (ESP)
Email & Lifecycle
Email Service Provider (ESP)
A platform used to build, send, and track marketing or transactional email at scale, such as Mailchimp, Klaviyo, or SendGrid.
By Brandon Mina·CEO, BrandPilot AI·Updated November 2026
Short answer
An email service provider (ESP) is a platform used to build, send and track marketing or transactional email at scale, such as Mailchimp, Klaviyo or SendGrid. ESPs manage subscriber lists, templates, automation and sending infrastructure. They also report on opens, clicks and bounces and help senders maintain deliverability and comply with anti-spam laws.