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About Me

I am contributing to and developing open-source software since 2011. Most of my work is related to the Android operating system. Examples of projects I significantly contributed to (and are not mentioned in the next section) include microG and OpenKeychain.

I graduated with a master in computer science and am a self-employed software engineer. My research and professional focus are in mobile privacy, IT security and fintech. I currently live in Berlin, Germany.

Me and XMPP

My first development activity around XMPP in 2012 was an open-source client for Android based on Smack. [1] It was a total mess and I discontinued work on it just a few months after publication. I also experimented with a system-wide XMPP service for Android in 2014, but it never became useful for anything. [2] In 2015, I participated in Google Summer of Code under the XSF to develop DNSSEC functionality for minidns. [3] While originally developed for the use in Smack, it is now also used in Conversations as well as many other projects.

Since 2016, I am one of the main developers of Dino. Since 2018 I (co-)mentor Google Summer of Code students for Dino. I regularly participate in development sprints and help advertise XMPP on conferences. I am happily contributing my opinion on the mailing list and in xsf@ MUC. I became a member of XSF in 2019. Since 2021, I serve on the XMPP Council.

My personal interest in XMPP is user-friendly and secure personal and team communication (chats and calls) - this excludes IoT / machine-to-machine communication. I am happy to contribute further to XEPs as well as Dino and other XMPP-related open source projects, to make this reality.

(Co-)authored XEPs

XEP Title
0384 OMEMO Encryption
0421 Anonymous unique occupant identifiers for MUCs
0426 Character counting in message bodies
0444 Message Reactions
0446 File metadata element
0447 Stateless file sharing
0448 Encryption for stateless file sharing
0449 Stickers
0461 Message Replies
0463 MUC Affiliations Versioning

Meetups, Sprints and Conferences

Collection of Events where I participated to chat or work on XMPP things.

When? Where? What?
January 2016 Brussels, Belgium FOSDEM 2016
August 2018 Cambridge, United Kingdom Sprint
December 2018 Leipzig, Germany 35th Chaos Communcation Congress
May 2019 Karlsruhe, Germany Sprint at 19th Gulaschprogrammiernacht
July 2019 Lyon, France Sprint
August 2019 Bonn, Germany FrOSCon 14
August 2019 Zehdenick, Germany Chaos Communication Camp 2019
September 2019 Berlin, Germany Meetup
September 2019 Stockholm, Sweden Sprint
October 2019 Munich, Germany Meetup during GSoC 2019 Mentor Summit
December 2019 Leipzig, Germany Sprint at 36th Chaos Communcation Congress
January 2020 Brussels, Belgium Summit 24
February 2020 Brussles, Belgium FOSDEM 2020
March 2020 Duesseldorf, Germany OMEMO Sprint
March 2020 Berlin, Germany Online Sprint
Since July 2022 (monthly) Berlin, Germany Meetup
August 2022 Bonn, Germany FrOSCon 17


  • Full name: Marvin Wißfeld
  • XMPP address: jabber at
  • e-Mail address: xmpp at
  • XSF discussion username: larma
  • Mastodon: