At Stalwart Labs, security is at the heart of everything we build. As part of our ongoing commitment to delivering a trustworthy email and collaboration server, we recently completed our second independent security audit, conducted by Radically Open Security. Our previous audit took place exactly two years ago, in 2023 — and with significant changes to our codebase since then, a fresh and thorough assessment was essential.
We’re excited to announce that Stalwart has been selected to participate in Session 2 of GitHub’s Open Source Secure Fund (OSSF), a prestigious program designed to enhance security across the open source ecosystem. This recognition represents not only an acknowledgment of Stalwart’s growing importance in the email infrastructure space but also our commitment to maintaining the highest security standards.
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.
Since we officially started developing Stalwart on September 4th, 2021, we’ve come a long way in establishing a powerful and versatile open-source mail and collaboration server. The very first commit, made on October 3rd, 2021, was to the mail-parser Rust crate, a fundamental component upon which Stalwart was built. It set the tone for our relentless pursuit of secure, reliable, and performant software.
We’re excited to announce the release of Stalwart v0.12, a significant milestone that evolves Stalwart from a powerful mail server into a complete, integrated communication and collaboration platform. This release delivers one of the most anticipated features from our community: native support for calendars, contacts, and file storage—all built directly into the server, with no need for third-party integrations.
