Compare the Top SMTP Services that integrate with IBM Cloud as of October 2025

This a list of SMTP services that integrate with IBM Cloud. Use the filters on the left to add additional filters for products that have integrations with IBM Cloud. View the products that work with IBM Cloud in the table below.

What are SMTP Services for IBM Cloud?

SMTP services and SMTP relay services enable organizations to send emails, including bulk emails to customers and users from their website. SMTP service providers provide an SMTP server that can be hosted or used on-premise so websites can send emails and ensure high deliverability of emails and mass email campaigns. Mail transfer agent (MTA) services are part of SMTP services. Compare and read user reviews of the best SMTP services for IBM Cloud currently available using the table below. This list is updated regularly.

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    Postfix

    Postfix

    Postfix

    What is Postfix? It is Wietse Venema's mail server that started life at IBM research as an alternative to the widely-used Sendmail program. Now at Google, Wietse continues to support Postfix. Postfix runs (or has run) on AIX, BSD, HP-UX, IRIX, LINUX, MacOS X, Solaris, Tru64 UNIX, and other UNIX systems. It requires ANSI C, a POSIX.1 library, and BSD sockets. Postfix attempts to be fast, easy to administer, and secure. The outside has a definite Sendmail-ish flavor, but the inside is completely different. Multiple SMTP deliveries over the same TLS-encrypted connection. This reuses the existing tlsproxy(8) and scache(8) services. MySQL stored procedure support. Gradual degradation: in many cases a Postfix daemon will log a warning and continue providing the services that are still available, instead of immediately terminating with a fatal error. Postfix can set the execute bit on a queue file. If this does not work, then no mail will ever be delivered.
  • 2
    Sendmail

    Sendmail

    Proofpoint

    The sendmail Sentrion platform is specifically designed for large, complex environments, but we make a subset of that solution available as an open-source offering. Sentrion is not for everyone, but if you are using open source email for a large complex environment and need an enterprise platform that will enable your messaging roadmap for years to come (virtualization, consolidation, cloud migration, etc.). The Domain Keys Identified Mail (DKIM) Internet standard enables email senders to digitally sign their messages so that receivers can verify that those messages have not been forged. The DKIM sender authentication scheme allows the recipient of a message to confirm a message originated with the sender’s domain and that the message content has not been altered. A cryptography-based solution, DKIM provides businesses an industry-standard method for mitigating email fraud and protecting an organization’s brand and reputation at a relatively low implementation cost.
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