Postmark is an email service provider specializing in fast, transactional email delivery (such as password resets, notifications, and order confirmations) via SMTP and API. It has separate infrastructure for promotional and transactional streams.
Klaviyo is an email marketing platform that helps e-commerce brands send personalized, data-driven campaigns. It offers advanced segmentation, automation, and analytics to optimize customer engagement and sales.
Brevo is a marketing platform that helps businesses send email campaigns, automate marketing workflows, and manage customer relationships. It offers tools for email, SMS, CRM, and more—all in one place.
