Trustworthy Calendar And Encryption For Self-Hosted JMAP Webmail
Bulwark is a modern open-source webmail client for the Stalwart mail server over JMAP, bundling email, calendar, contacts, and files, and it reached 611 GitHub stars from self-hosters modernizing their mail stack, but its issues show the trust-critical gaps: no S/MIME support to read encrypted mail, all-day events rendering wrong in CalDAV clients, calendar attendees not actually invited on save, and connection failures against current Stalwart versions. Self-hosters want a modern webmail whose calendar and encryption just work. The wedge is reliable calendar interop and S/MIME for the modern JMAP self-hosting stack.
Problem Statement
A self-hoster runs Stalwart and adopts a modern webmail, but it cannot read their S/MIME-encrypted mail, all-day events show on the wrong days in Thunderbird and iOS, calendar attendees are never actually invited when an event is saved, and it fails to connect to the current Stalwart version. The modern client cannot reliably handle their calendar and encrypted mail, so they fall back to clunky older webmail or a hosted provider.
The Idea
A modern self-hosted webmail client for the JMAP and Stalwart stack with dependable calendar interoperability and S/MIME encryption support.
Why Now
Self-hosted email had a renaissance in 2026 around the Stalwart server and the JMAP protocol, and people want a modern webmail to match, but Bulwark's issues show calendar interop and encryption are unsolved, the exact features that decide whether a self-hosted mail stack can replace a hosted provider.
Target User
Self-hosters and privacy-focused users running Stalwart and JMAP mail stacks
Target Market
Self-hosted email and webmail client software
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