What is the difference between ESP and SMTP provider?

ESPs (Email Service Providers) offer complete email marketing platforms: campaign design, list management, scheduling, analytics, compliance features, and delivery. They're business solutions for marketing teams. Mailchimp, Klaviyo, Smaily, and Brevo are ESPs.

SMTP providers offer infrastructure: servers, IP addresses, and connections for transmitting email. They focus on delivery mechanics rather than marketing features. Amazon SES, Mailgun, and SparkPost function primarily as SMTP providers, though some add marketing features.

Many senders use both: an ESP for marketing campaigns with rich features, plus an SMTP provider for transactional email needing high-speed delivery. The distinction isn't always sharp; some providers offer both capabilities. Choose based on whether you need marketing tools or infrastructure capacity.