After four years of development, we’re thrilled to announce a major milestone in the evolution of Stalwart — the full implementation of JMAP for Calendars, Contacts, Address Books, File Storage, and Sharing. With this release, Stalwart becomes the first JMAP server to fully support the entire family of JMAP collaboration protocols, marking a new era for open, efficient, and elegant groupware.
Over the past few years, the IETF has been redefining how email, calendars, and contacts are synchronized and shared. Building upon the success of JMAP for Mail, several new protocol extensions have been introduced:
Together, these standards offer a cohesive and elegant ecosystem that replaces decades of fragmented WebDAV-based technologies.
WebDAV and its descendants — CalDAV, CardDAV, and related extensions — have served the Internet well. They are robust, widely adopted, and battle-tested. Yet, their XML-based design is notoriously verbose, inconsistent, and difficult to implement correctly. Information is scattered across HTTP headers, XML payloads, and even embedded iCalendar data, creating endless compatibility and interoperability challenges between clients and servers.
Similarly, iCalendar and vCard, while expressive and versatile, have accumulated decades of technical debt. They contain countless properties and parameters—many rarely used, some obsolete, and others inconsistently implemented across versions. This clutter has made both formats unwieldy and error-prone, often requiring complex parsing logic to handle edge cases.
The JMAP protocol was originally developed as a more efficient, modern replacement for IMAP and SMTP submissions. Its strengths lie in simplicity, clarity, and network efficiency — all built on top of JSON over HTTPS.
Now, with the introduction of JMAP for Calendars, Contacts, Files, and Sharing, the same design philosophy extends beyond email to the entire collaboration stack. These protocols deliver what DAV always aimed for but never quite achieved: a clean, uniform, and easily implementable API for all personal and group data — mail, calendars, contacts, files, and shared resources.
Meanwhile, JSCalendar and JSContact reimagine iCalendar and vCard as elegant JSON-based formats. They strip away decades of accumulated cruft, unify representations, and offer a clear, unambiguous, and expressive data model. Both are human-readable, developer-friendly, and efficient to parse — a perfect fit for modern applications.
Together, JMAP and these new data models make calendaring, contact management, and file sharing not only easier to implement but also faster and more reliable.
This release represents more than new features — it marks a shift in how groupware protocols are designed and implemented. For the first time, developers and organizations can build on a single, coherent, JSON-based framework for mail, contacts, calendars, and shared resources.
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