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mta-hooks

2 posts with the tag “mta-hooks”

MTA Hooks at the IETF

- 7 min read
Mauro D.
Mauro D.
Project Maintainer

Two years ago we shipped MTA Hooks in Stalwart Mail Server as a modern, HTTP-based alternative to Milter. In the time since, it has gone from a Stalwart feature to a protocol used across thousands of deployments worldwide, with implementations being built by third parties and interest from major players in the mail filtering ecosystem. We are now taking the next step: standardizing MTA Hooks at the IETF, so that it stops being “the Stalwart way of doing things” and becomes an open protocol that any MTA and any filter can speak.

Introducing Virtual Queues and Strategy-Driven Delivery in Stalwart MTA

- 4 min read
Mauro D.
Mauro D.
Project Maintainer

At Stalwart Labs, we’re constantly working to evolve and improve our software based on real-world feedback. Today, we’re excited to announce a major enhancement to the queueing system in Stalwart MTA, designed to meet the needs of some of our busiest users—those delivering millions of messages per day.

This update is the result of valuable input from operators managing large-scale mail infrastructure. Many reported a recurring issue: when message volumes spiked, low-priority traffic, such as DMARC aggregate reports and Delivery Status Notifications (DSNs), would often compete with or delay the delivery of legitimate user mail. Since all messages were processed through a single delivery queue, these traffic types were treated equally, regardless of urgency or purpose.