Fast, Flexible, Open-Source

The best MTA for
Enterprise Senders


KumoMTA is architected for the performance needed by enterprise senders, whether it's sending several million messages per hour through a single server, or scaling horizontally using Docker and Kubernetes.


KumoMTA can replace straightforward configurations or be deeply integrated into your MailOps environment thanks to our Lua scripting engine and support for technologies including webhooks, AMQP, Kafka, Vault, Prometheus, Grafana, and direct database access.


KumoMTA is released under the Apache 2 OSI-approved license, with the ultimate transparency of having our sourcecode hosted on Github. Our community is actively involved and contributing to make KumoMTA better every day.

Making KumoMTA Possible For All

Our Sponsors

Our Growing Community

42000 +

Lines of Source Code

250 +

Pages of Documentation

290 +

Discord Members

180 +

Stars on GitHub

Join Our Community

Our Users


Taguchi Marketing

Ben Dyer

"We’ve known Kumo’s founders and worked with them for many years, That personal connection was critical.

The fact they’re involved was enough to get us over the line to becoming a customer."

Our Partners

ongage logo
Integration Partner


Ongage is an email marketing platform that helps your business to personalize engagements and drive conversions through data.
Services Partner


Postmastery is a leader in email deliverability and infrastructure management. They offer professional tools for email delivery and monitoring, enabling legitimate email senders to optimize their infrastructure and practices for email marketing and transactional email applications.
Services Partner


Edgeneering LLC is a Web Development and technology company specializing in software & database development, high security data center hosting, and Open-Source consulting services.

Our Latest Blog Posts

User Spotlight: Mailtinni

KumoMTA was created as a platform for others to build email services on. Our extensive documentation was written...

ARM Yourself With the KumoMTA Spring Release

We're pleased to announce that the new KumoMTA Spring Release is now available in GA!

Protect Your Deliverability With An Abuse Page

When you operate a multi tenant sending environment compliance is a major portion of your operations, and yet on...

Choose the Best MTA

Find out more about how you can break free of the commercial license trap while leveraging the best MTA for enterprise senders.

Let's Talk

Chat with our founders and learn how easy it can be to move to KumoMTA.