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.
Mailchimp is an email marketing platform that allows users to create, send, and automate newsletters and campaigns. It includes tools for audience management, analytics, and marketing automation.
