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JMAP support (replacement for the limited imap/smtp/caldav/cardav Protocols)

Feature RequestIntegrations

Thunderbird is currently in the testing phase for Thunderbird Pro, based on the relatively new JMAP protocol, also allowing a more streamlined experience, especially regarding the somewhat limited calendar function via CalDAV (calendar invites only arrive as ICS files via email, for example). I'm aware that there aren't many providers yet supporting JMAP, but for me, that's one of the major issues that keeps me partially hooked to the Microsoft ecosystem.

JMAP Project Website: https://jmap.io/

Posted by Micha Dettwiler ·
2 comments

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Comments2

  • Marco Ancona

    Team•

    Nov 28, 2025

    We are aware of the JMAP protocol, and we keep monitoring the evolution in the space with trepidation (hoping to be able to drop CalDAV one day! 😅).
    Our data model is already based on the JSCalendar standard, but currently, we don’t support JMAP for syncing simply because there are no providers with public APIs using it. Are you aware of any?

    • mike

      •

      Dec 23, 2025

      Apart from Fastmail, I have only found Thunderbird Pro and Stalwart mentioning jmap support. I hope that Infomaniak will adopt it. They responded to my request, but there are no plans yet.

      To be fair, my main issue is with Microsoft handling non-Exchange calendars differently and receiving CalDAV event invitations as ICS mail attachments. Without Microsoft accepting the JMAP standard, I doubt the experience will change much.

      Still, at least it would add much needed features ms365 externally.