Compare Greatmail vs. OpenSMTPD

Reliable cloud-based email hosting includes features such as spam filtering, antivirus protection, ample storage, and webmail access. It seamlessly integrates with Outlook as well as various other POP3/IMAP clients. For users with high sending needs, it offers a robust SMTP service designed for responsible senders. Additionally, there is an outbound relay service tailored for transactional emails, marketing campaigns, newsletters, and diverse applications. The infrastructure supports dedicated email servers, clustering, and multiple IP load balancing to accommodate high-volume senders effectively. With a fixed monthly fee, users benefit from unlimited sending capabilities and reputation monitoring. Greatmail stands out as an email service provider (ESP) focused on delivering business-class email hosting, SMTP hosting, and specialized email servers. Furthermore, for ISPs, software developers, and cloud architects, we also create custom solutions featuring dedicated IP servers and load-balanced configurations with multiple servers to meet specific processing needs. This commitment to adaptability ensures that all clients receive the best possible service, tailored to their unique requirements.

OpenSMTPD serves as a free implementation of the SMTP protocol for server-side email communication, as laid out in RFC 5321, and incorporates several additional standard extensions. This software enables standard machines to facilitate email exchanges with other systems that also utilize the SMTP protocol. Born from a desire for a more satisfactory alternative to existing solutions, OpenSMTPD offers a comprehensive SMTP implementation. The project is mainly driven by developers Gilles Chehade and Eric Faurot, alongside contributions from numerous OpenBSD developers and collaborators from various other communities. Its development reflects a commitment to improving email server functionality and reliability across different platforms.