Mailgun is the email automation engine for sending, receiving and tracking emails. Developed by Rackspace, US Inc.
License: Freemium
Mailgun is primarily focused on email delivery and provides robust analytics and integrations for developers, making it ideal for transactional email use cases. In contrast, Atomic Email Tracker offers a more user-friendly approach to tracking email interactions, making it suitable for small businesses and individuals looking to monitor their email campaigns.