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Stalwart Blog

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.

The Future of Stalwart: Webmail, Roadmap, and Beyond

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

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.

Introducing Calendars, Contacts and Files in Stalwart

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

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.

Stalwart Receives NLNet Grant to Build Collaboration Server

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

We’re happy to announce that Stalwart Labs has been awarded a new grant from the NGI0 Core Fund, established by NLnet with financial support from the European Commission’s Next Generation Internet programme. This funding will support the development of essential collaboration features, marking a major milestone in Stalwart’s evolution from a modern email server into a complete, self-hosted collaboration platform.

This is the second grant Stalwart has received from NLnet, following the initial support we received in March 2023 from the NGI0 Entrust Fund. We are deeply grateful to the NLnet Foundation for their continued trust in our mission to modernize and decentralize communication infrastructure.

OpenID Connect Integration is now Open Source

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

We are happy to announce that third-party OpenID Connect (OIDC) authentication support has now been open-sourced under the AGPL-3.0 license in Stalwart Mail Server version 0.11.5. This means that users can now configure Stalwart Mail Server to authenticate against external OIDC providers, such as Keycloak, without requiring an Enterprise subscription.

Stalwart Mail Server has supported OIDC authentication for several months, allowing it to function as either an OIDC provider or an OIDC client authenticating against an external provider. Until now, only the ability to act as an OIDC provider was included in the Open Source edition, while authentication via external OIDC providers was reserved for Enterprise users. By making this functionality freely available, we are reinforcing our commitment to openness and ensuring that more users can take advantage of modern, federated authentication without barriers.

With this change, organizations that rely on external OIDC identity providers can seamlessly integrate Stalwart Mail Server into their existing authentication workflows at no cost. Whether you are using Keycloak, Auth0, or another OIDC-compliant solution, Stalwart Mail Server now offers complete flexibility in how you manage authentication.