FOSDEM on Matrix

February 15, 2021

Well, that was pretty wild!

We’re very proud to have sponsored FOSDEM this year, and to have had extra skin in the game by helping FOSDEM go virtual. There is a full write up about how Matrix at FOSDEM worked on the Matrix blog, so we’ll just cover a few highlights here.

For those that don’t already know, FOSDEM is the world’s largest free and open source software conference. It’s usually an in-person event but - no surprise - that wasn’t going to happen in February 2021.

Spinning it up

To help going virtual be as smooth as possible, we hosted FOSDEM on Element Matrix Services (EMS). Piggy-backing on that existing infrastructure is quicker and easier than an on-premise deployment, but still provides data sovereignty given you can use your own DNS records.

Such flexibility meant that FOSDEM was able to have a communications infrastructure to support 35,000 attendees for a two day event, complete with video conferencing, used to host all the Q&A sessions, hallway sessions, stands and other adhoc video conferences.

A Matrix bot, written from scratch for FOSDEM by Element’s TravisR, orchestrated the overall conference on Matrix, maintaining all the necessary rooms with the correct permissions, widgets, invites, etc.

A home without walled gardens

With Matrix being an open standard, anyone already on Matrix (including users bridged to Matrix from IRC, XMPP, Slack, Discord etc) could attend directly - in addition to users signing up for the first time on the FOSDEM server.

Such inclusivity helped generate some impressive statistics:

  • Almost 30,000 local users on the (EMS hosted) FOSDEM server + 4,000 remote users from elsewhere in Matrix
  • 24,826 guests (read-only invisible users) on the FOSDEM server
  • More than 8,000 distinct users actively joined to the public FOSDEM rooms
  • …of which almost 4,000 registered on the FOSDEM server (meaning over half of actively participating attendees for FOSDEM were already on Matrix!)
  • These numbers don’t count users who were viewing the livestreams directly, but only those who were attending via Matrix


For FOSDEM to trust us with its virtual debut was a huge honour, and we’re delighted that it worked out well.

For more details read Matthew’s post, watch the talk about FOSDEM-on-Matrix in this month’s Open Tech Will Save Us meetup or the Building Massive Virtual Communities on Matrix talk at FOSDEM.

As for next year…

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