Category – General
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Element raises $30M to boost Matrix

2021-07-27 — General, News — Matthew Hodgson

Hi folks,

Big news today: Element, the startup founded by the team who created Matrix, just raised $30M of Series B funding in order to further accelerate Matrix development and improve Element, the flagship Matrix app. The round is led by our friends at Protocol Labs and Metaplanet, the fund established by Jaan Tallinn (co-founder of Skype and Kazaa). Both Protocol Labs and Metaplanet are spectacularly on board our decentralised communication quest, and you couldn't really ask for a better source of funding to help take Matrix to the next level. Thank you for believing in Matrix and leading Element's latest funding!

You can read all about it from the Element perspective over at the Element Blog, but suffice it to say that this is enormous news for the Matrix ecosystem as a whole. In addition to transforming the Element app, on the Matrix side this means that there is now concrete funding secured to:

Obviously this is in addition to all the normal business-as-usual work going on in terms of:

  • getting Spaces out of beta
  • adding Threading to Element (yes, it's finally happening!)
  • speeding up room joins over federation
  • creating 'sync v3' to lazy-load all content and make the API super-snappy
  • lots of little long-overdue fun bits and pieces (yes, custom emoji, we're looking at you).

If you're wondering whether Protocol Labs' investment means that we'll be seeing more overlap between IPFS and Matrix, then yes - where it makes tech sense to do so, we're hoping to work more closely together; for instance collaborating with the libp2p team on our P2P work (we still need to experiment properly with gossipsub!), or perhaps giving MSC2706 some attention. However, there are no plans to use cryptocurrency incentives in Matrix or Element any time soon.

So, exciting times ahead! We'd like to inordinately thank everyone who has supported Matrix over the years - especially our Patreon supporters, whose donations pay for all the infrastructure while inspiring others to open their cheque books; the existing investors at Element (especially Notion and Automattic, who have come in again on this round); all the large scale Matrix deployments out there which are effectively turning Matrix into an industry (hello gematik!) - and everyone who has ever run a Matrix server, contributed code, used the spec to make their own Matrix-powered creation, or simply chatted on Matrix.

Needless to say, Matrix wouldn't exist without you: the protocol and network would have fizzled out long ago were it not for all the people supporting it (the server can now see over 35.5M addressable users on the network!) - and meanwhile the ever-increasing energy of the community and the core team combines to keep the protocol advancing forwards faster than ever.

We will do everything we possibly can to succeed in creating the long-awaited secure communication layer of the open Web, and we look forward to large amounts of Element's new funding being directed directly into core Matrix development :)

thanks for flying Matrix,

Matthew, Amandine & the whole Matrix core team.

Germany’s national healthcare system adopts Matrix!

2021-07-21 — General, News — Matthew Hodgson

Hi folks,

We’re incredibly excited to officially announce that the national agency for the digitalisation of the healthcare system in Germany (gematik) has selected Matrix as the open standard on which to base all its interoperable instant messaging standard - the TI-Messenger.

gematik has released a concept paper that explains the initiative in full.


With the TI-Messenger, gematik is creating a nationwide decentralised private communication network - based on Matrix - to support potentially more than 150,000 healthcare organisations within Germany’s national healthcare system. It will provide end-to-end encrypted VoIP/Video and messaging for the whole healthcare system, as well as the ability to share healthcare based data, images and files.

Initially every healthcare provider (HCP) with an HBA (HPC ID card) will be able to choose their own TI-Messenger provider. The homesever for HCP accounts will be hosted by the provider’s datacentre. The homeserver for institutions can be hosted by TI-Messenger providers, or on-premise.

Each organisation and individual will therefore retain complete ownership and control of their communication data - while being able to share it securely within the healthcare system with end-to-end encryption by default. All servers in the Matrix-based private federation will be hosted within Germany.

Needless to say, security is key when underpinning the entire nation’s healthcare infrastructure and safeguarding sensitive patient data. As such, the entire implementation will be accredited by BSI (Federal Office for Information Security) and BfDI (Federal Commissioner for Data Protection and Freedom of Information).

The full context...

Germany’s digital care modernisation law (“Digitale Versorgung und Pflege Modernisierungs Gesetz” or DVPMG), which came into force in June 2021, spells out the need for an instant messaging solution.

The urgency has increased by a significant rise in the use of instant messaging and video conferencing within the healthcare system - for instance, the amount of medical practices using messenger services doubled in 2020 compared to 2018 (much of this using insecure messaging solutions).

gematik, majority-owned by Germany’s Federal Ministry of Health, is responsible for the standardised digital transformation of Germany’s healthcare sector. It focuses on improving efficiency and introducing new ways of working by setting, testing and certifying healthcare technology including electronic health cards, electronic patient records and e-prescriptions.

TI-Messenger is gematik’s technical specification for an interoperable secure instant messaging standard. The healthcare industry will be able to build a wide range of apps based on TI-Messenger specifications knowing that, being built on Matrix, all those apps will interoperate.

More than 150,000 organisations - ranging from local doctors to clinics, hospitals, and insurance companies - can potentially standardise on instant messaging thanks to gematik’s TI-Messenger initiative.

The road to interoperability

By 1 October 2021, TI-Messenger will initially specify how communication should work in practice between healthcare professionals (HCPs). Physicians will be able to find and communicate with each other via TI-Messenger approved apps - specifications include secure authentication mechanisms with electronic health professional cards (eHBAs), electronic institution cards (SMC-B) and a central FHIR directory. The first compliant apps for HCPs are expected to be licensed by Q2 2022.

Eric Grey (product manager for TI-Messenger at gematik), reckons there will initially be around 10-15 TI-Messenger compliant Matrix-based apps for HCP communications available from different vendors.

Healthcare professionals will be able to choose a TI-Messenger provider, who will be hosting their personal accounts and provide the messenger-client.

Healthcare organisations will choose a TI-Messenger provider to build the dedicated homeserver infrastructure (on prem or in a data center), provide the client and ongoing support.

What does this mean for the Matrix community?

Matrix is already integral to huge parts of the public sector; from the French government’s Tchap platform, to Bundeswehr’s use of BwMessenger and adoption by universities and schools across Europe.

Germany’s healthcare system standardising on Matrix takes this to entirely the next level - and we can’t wait to see the rest of Europe (and the world!) converge on Matrix for healthcare!

We'll have more info about TI-Messenger on this week's Matrix Live, out on Friday - stay tuned!

How the UK's Online Safety Bill threatens Matrix

2021-05-19 — Tech, General — Denise Almeida

Last week the UK government published a draft of the proposed Online Safety Bill, after having initially introduced formal proposals for said bill in early 2020. With this post we aim to shed some light on its potential impacts and explain why we think that this bill - despite having great intentions - may actually be setting a dangerous precedent when it comes to our rights to privacy, freedom of expression and self determination.

The proposed bill aims to provide a legal framework to address illegal and harmful content online. This focus on “not illegal, but harmful” content is at the centre of our concerns - it puts responsibility on organisations themselves to arbitrarily decide what might be harmful, without any legal backing. The bill itself does not actually provide a definition of harmful, instead relying on service providers to assess and decide on this. This requirement to identify what is “likely to be harmful” applies to all users, children and adults. Our question here is - would you trust a service provider to decide what might be harmful to you and your children, with zero input from you as a user?

Additionally, the bill incentivises the use of privacy-invasive age verification processes which come with their own set of problems. This complete disregard of people’s right to privacy is a reflection of the privileged perspectives of those in charge of the drafting of this bill, which fails to acknowledge how actually harmful it would be for certain groups of the population to have their real life identity associated with their online identity.

Our view of the world, and of the internet, is largely different from the one presented by this bill. Now, this categorically does not mean we don’t care about online safety (it is quite literally our bread and butter) - we just fundamentally disagree with the approach taken.

Whilst we sympathise with the government’s desire to show action in this space and to do something about children’s safety (everyone’s safety really), we cannot possibly agree with the methods.

Back in October of 2020 we presented our proposed approach to online safety - ironically also in response to a government proposal, albeit about encryption backdoors. In it, we briefly discussed the dangers of absolute determinations of morality from a single cultural perspective:

As uncomfortable as it may be, one man’s terrorist is another man’s freedom fighter, and different jurisdictions have different laws - and it’s not up to the Foundation to play God and adjudicate.

We now find ourselves reading a piece of legislation that essentially demands these determinations from tech companies. The beauty of the human experience lies with its diversity and when we force technology companies to make calls about what is right or wrong - or what is “likely to have adverse psychological or physical impacts” on children - we end up in a dangerous place of centralising and regulating relative morals. Worst of all, when the consequence of getting it wrong is criminal liability for senior managers what do we think will happen?

Regardless of how omnipresent it is in our daily lives, technology is still not a solution for human problems. Forcing organisations to be judge and jury of human morals for the sake of “free speech” will, ironically, have severe consequences on free speech, as risk profiles will change for fear of liability.

Forcing a “duty of care” responsibility on organisations which operate online will not only drown small and medium sized companies in administrative tasks and costs, it will further accentuate the existing monopolies by Big Tech. Plainly, Big Tech can afford the regulatory burden - small start-ups can’t. Future creators will have their wings clipped from the offset and we might just miss out on new ideas and projects for fear of legal repercussions. This is a threat to the technology sector, particularly those building on emerging technologies like Matrix. In some ways, it is a threat to democracy and some of the freedoms this bill claims to protect.

These are, quite frankly, steps towards an authoritarian dystopia. If Trust & Safety managers start censoring something as natural as a nipple on the off chance it might cause “adverse psychological impacts” on children, whose freedom of expression are we actually protecting here?

More specifically on the issue of content moderation: the impact assessment provided by the government alongside this bill predicts that the additional costs for companies directly related to the bill will be in the billions, over the course of 10 years. The cost for the government? £400k, in every proposed policy option. Our question is - why are these responsibilities being placed on tech companies, when evidently this is a societal problem?

We are not saying it is up to the government to single-handedly end the existence of Child Sexual Abuse and Exploitation (CSAE) or extremist content online. What we are saying is that it takes more than content filtering, risk assessments and (faulty) age verification processes for it to end. More funding for tech literacy organisations and schools, to give children (and parents) the tools to stay safe is the first thing that comes to mind. Further investment in law enforcement cyber units and the judicial system, improving tech companies’ routes for abuse reporting and allowing the actual judges to do the judging seems pretty sensible too. What is absolutely egregious is the degradation of the digital rights of the majority, due to the wrongdoings of a few.

Our goal with this post is not to be dramatic or alarmist. However, we want to add our voices to the countless digital rights campaigners, individuals and organisations that have been raising the alarm since the early days of this bill. Just like with coercive control and abuse, the degradation of our rights does not happen all at once. It is a slippery slope that starts with something as (seemingly) innocuous as mandatory content scanning for CSAE content and ends with authoritarian surveillance infrastructure. It is our duty to put a stop to this before it even begins.

Twitter card image credit from Brazil, which feels all too familiar right now.

The Matrix Space Beta!

2021-05-17 — Tech, General — Matthew Hodgson

Hi all,

As many know, over the years we've experimented with how to let users locate and curate sets of users and rooms in Matrix. Back in Nov 2017 we added 'groups' (aka 'communities') as a custom mechanism for this - introducing identifiers beginning with a + symbol to represent sets of rooms and users, like

However, it rapidly became obvious that Communities had some major shortcomings. They ended up being an extensive and entirely new API surface (designed around letting you dynamically bridge the membership of a group through to a single source of truth like LDAP) - while in practice groups have enormous overlap with rooms: managing membership, inviting by email, access control, power levels, names, topics, avatars, etc. Meanwhile the custom groups API re-invented the wheel for things like pushing updates to the client (causing a whole suite of problems). So clients and servers alike ended up reimplementing large chunks of similar functionality for both rooms and groups.

And so almost before Communities were born, we started thinking about whether it would make more sense to model them as a special type of room, rather than being their own custom primitive. MSC1215 had the first thoughts on this in 2017, and then a formal proposal emerged at MSC1772 in Jan 2019. We started working on this in earnest at the end of 2020, and christened the new way of handling groups of rooms and users as... Spaces!

Spaces work as follows:

  • You can designate specific rooms as 'spaces', which contain other rooms.
  • You can have a nested hierarchy of spaces.
  • You can rapidly navigate around that hierarchy using the new 'space summary' (aka space-nav) API - MSC2946.
  • Spaces can be shared with other people publicly, or invite-only, or private for your own curation purposes.
  • Rooms can appear in multiple places in the hierarchy.
  • You can have 'secret' spaces where you group your own personal rooms and spaces into an existing hierarchy.

Today, we're ridiculously excited to be launching Space support as a beta in matrix-react-sdk and matrix-android-sdk2 (and thus Element Web/Desktop and Element Android) and Synapse 1.34.0 - so head over to your nearest Element, make sure it's connected to the latest Synapse (and that Synapse has Spaces enabled in its config) and find some Space to explore! might be a good start :)

The beta today gives us the bare essentials: and we haven't yet finished space-based access controls such as setting powerlevels in rooms based on space membership (MSC2962) or limiting who can join a room based on their space membership (MSC3083) - but these will be coming asap. We also need to figure out how to implement Flair on top of Spaces rather than Communities.

This is also a bit of a turning point in Matrix's architecture: we are now using rooms more and more as a generic way of modelling new features in Matrix. For instance, rooms could be used as a structured way of storing files (MSC3089); Reputation data (MSC2313) is stored in rooms; Threads can be stored in rooms (MSC2836); Extensible Profiles are proposed as rooms too (MSC1769). As such, this pushes us towards ensuring rooms are as lightweight as possible in Matrix - and that things like sync and changing profile scale independently of the number of rooms you're in. Spaces effectively gives us a way of creating a global decentralised filesystem hierarchy on top of Matrix - grouping the existing rooms of all flavours into an epic multiplayer tree of realtime data. It's like USENET had a baby with the Web!

For lots more info from the Element perspective, head over to the Element blog. Finally, the point of the beta is to gather feedback and fix bugs - so please go wild in Element reporting your first impressions and help us make Spaces as awesome as they deserve to be!

Thanks for flying Matrix into Space;

Matthew & the whole Spaces (and Matrix) team.

How we hosted FOSDEM 2021 on Matrix

2021-02-15 — General — Matthew Hodgson

Hi all,

Just over a week ago we had the honour of using Matrix to host FOSDEM: the world's largest free & open source software conference. It's taken us a little while to write up the experience given we had to recover and catch up on business as usual... but better late than never, here's an overview of what it takes to run a ~30K attendee conference on Matrix!

[confetti and firework easter-eggs explode over the closing keynote of FOSDEM 2021]

First of all, a quick (re)introduction to Matrix for any newcomers: Matrix is an open source project which defines an open standard protocol for decentralised communication. The global Matrix network makes up at least 28M Matrix IDs spread over around 60K servers. For FOSDEM, we set up a server to host newcomers, provided by Element Matrix Services (EMS) - Element being the startup formed by the Matrix core team to help fund Matrix development.

The most unique thing about Matrix is that conversations get replicated across all servers whose users are present in the conversation, so there's never a single point of control or failure for a conversation (much as git repositories get replicated between all contributors). And so hosting FOSDEM in Matrix meant that everyone 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. Therefore the chat around FOSDEM 2021 now exists for posterity on all the Matrix servers whose users who participated; and we hope that the server will hang around for the benefit of all the newcomers for the forseeable so they don't lose their accounts!

Talking of which: the vital stats of the weekend were as follows:

  • We saw almost 30K local users on the FOSDEM server + 4K remote users from elsewhere in Matrix.
  • There were 24,826 guests (read-only invisible users) on the FOSDEM server.
  • There were 8,060 distinct users actively joined to the public FOSDEM rooms...
  • ...of which 3,827 registered on the FOSDEM server. (This is a bit of an eye-opener: over 50% of the 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.

Given last year's FOSDEM had roughly 8,500 in-person attendees at the Université libre de Bruxelles, this feels like a pretty good outcome :)

Graphwise, local user activity on the FOSDEM server looked like this:

How was it built?

There were four main components on the Matrix side:

  1. A horizontally-scalable Matrix server deployment (Synapse hosted in EMS)
  2. A Jitsi cluster for the video conferencing, used to host all the Q&A sessions, hallway sessions, stands, and other adhoc video conferences
  3. An elastically scalable Jibri cluster used to livestream the Jitsi conferences both to the official FOSDEM livestreams and to provide a local preview of the conference on Matrix (to avoid the Jitsis getting overloaded with folks who just want to view)
  4. conference-bot - a Matrix bot which orchestrated the overall conference on Matrix, written from scratch for FOSDEM by TravisR, consuming the schedule from FOSDEM and maintaining all the necessary rooms with the correct permissions, widgets, invites, etc.

Architecturally, it looked like this:

On the clientside, we made heavy use of widgets: the ability to embed arbitrary web content as iframes into Matrix chatrooms. (Widgets currently exist as a set of proposals for the Matrix spec, which have been preemptively implemented in Element.)

For instance, the conference-bot created Matrix rooms for all the FOSDEM devrooms with a predefined widget for viewing the official FOSDEM livestream for that room, pointing at the appropriate HLS stream at - which looked like this:

Each devroom also had a schedule widget available on the righthand side, visualising the schedule of that room - huge thanks to Hato and Steffen and folks at Nordeck for putting this together at the last minute; it enormously helped navigate the devrooms (and even had a live countdown to help you track where you were at in the schedule!)

Each devroom was also available via IRC on Freenode via a dedicated bridge (#fosdem-...) and via XMPP.

The bot also created rooms for each and every talk at FOSDEM (all 666 of them), as the space where the speaker and host could hang out in advance; watch the talk together, and then broadcast the Q&A session. At the end of the talk slot, the bot then transformed the talk room into a 'hallway' for the talk, and advertised it to the audience in the devroom, so folks could pose follow-on questions to the speaker as so often happens in real life at FOSDEM. The speaker's view of the talk rooms looked like this:

On the right-hand side you can see a "scoreboard" - a simple widget which tracked which messages in the devroom had been most upvoted, to help select questions for the Q&A session. On the left-hand side you can see a hybrid Jitsi/livestream widget used to coordinate between the speaker & host. By default, the widget showed the local livestream of the video call - if you clicked 'join conference' you'd join the Jitsi itself. This stopped view-only users from overloading the Jitsi once the room became public.

The widgets themselves were hosted by the bot (you can see them at Meanwhile the webclient itself ended up being identical to mainline Element Web 1.7.19, other than FOSDEM branding and being configured to hook the 'video call' button up to the hybrid Jitsi/livestream widget rather than a plain Jitsi.

Meanwhile, for conferencing we hosted an off-the-shelf Jitsi cluster sized to ~100 concurrent conferences, and for the Jibri livestreaming we set up an elastic scalable cluster using AWS Auto Scaling Groups. Jibri is essentially a Chromium which views the Jitsi webapp, running in a headless X server whose framebuffer and ALSA audio is hooked up to an ffmpeg process which livestreams to the appropriate destination - so we chose to run a separate VM for every concurrent livestream to keep them isolated from each other. The Jibri ffmpegs compressed the livestream to RTMP and relayed it to our nginx, which in turn relayed it to FOSDEM's livestreaming infrastructure for use in the official stream, as well as relaying it back to the local video preview in the Matrix livestream/video widget.

Here's a screengrab of the Jitsi/Jibri Grafana dashboard during the first day of the conference, showing 46 concurrent conferences in action, with 25 spare jibris in the scaling group cluster ready for action if needed :)

There was also an explosion of changes to Element itself to try to make things go as smoothly as possible. Probably the most important one was implementing Social Login - giving single-click registration for attendees who were happy to piggyback on existing identity providers (GitHub, GitLab, Google, Apple and Facebook) rather then signing up natively in Matrix:

This was a real epic to get together (and is also an important part of achieving parity betwen Gitter and Element) - and seems to have been surprisingly successful for FOSDEM. Almost 50% of users who signed up on the FOSDEM server did so via social login! We should also be turning it on for the server this week.

Finally, on the Matrix server side, we ran a cluster of synapse worker processes (1 federation inbound, reader and sender, 1 pusher, 1 initial sync worker, 10 synchrotrons, 1 event persister, 1 event creator, 4 general purpose client readers, 1 typing worker and 1 user directory) within Kubernetes on EMS. These were hooked up for horizontal scalability as follows:

The sort of traffic we saw (from day 2) looked like this:

How did it go?

Overall, people seem to have had a good time. Some folks have even been kind enough to call it the best online event they've been to :) This probably reflects the fact that FOSDEM rocks no matter what - and that Matrix is an inherently social medium, built by and for open source communities (after all, the whole Matrix ecosystem is developed over Matrix!). Also, Matrix being an open network means that folks could join from all over, so the social dynamics already present in Matrix spilled over into FOSDEM - and we even saw a bunch of people spin up their own servers to participate; literally sharing the hosting responsibility themselves. Finally, having critical infrastructure rooms available such as, and probably helped as well.

That said, we did have some production incidents which impacted the event. The most serious one was on Saturday morning, where it transpired that some of the endpoints hosted on the main Synapse process were taking way more CPU than we'd anticipated - most importantly the /groups endpoints which handle traffic relating to communities (the legacy way of defining groups of rooms in Matrix). One of the last things we'd done to prepare for the conference on Friday night was to create a community which spanned all 1000 public rooms in the conference, as well as add the community to all of those rooms - and unfortunately we didn't anticipate how popular these would be. As a result we had to do some emergency rebalancing of endpoints, spinning up new workers and reconfiguring the loadbalancer to relieve load off the main process.

Ironically the Matrix server was largely working okay during this timeframe, given event-sending no longer passes through the main process - but the most serious impact was that the conference bot was unable to boot due to hitting a wide range of endpoints on startup as it syncs with the conference, some of which were timing out. This in turn impacted widgets, which had been hosted by the bot for convenience, meaning that the Jitsi conferences for stands and talk Q&A were unavailable (even though the Jitsi/Jibri cluster was fine). This was solved by lunchtime on Saturday: we are really sorry for folks whose Q&As or conferences got caught in this. On the plus side, we spotted that many affected rooms just added their own widgets for their own Jitsis or BBBs to continue with minimal distraction - effectively manually taking over from the bot.

The other main incident was briefly first thing on Sunday morning, where two Jibri livestreams ended up trying to broadcast video to the same RTMP URL (potentially due to a race when rapidly removing and re-adding the jitsi/livestream widget for one of the stands). This caused a cascading failure which briefly impacted all RTMP streams, but was solved within about 30 minutes. We also had a more minor problem with the active speaker recognition malfunctioning in Jitsi on Sunday (apparently a risk when using SCTP rather than Websockets as a transport within Jitsi) - this was solved around lunchtime. Again, we're really sorry if you were impacted by this. We've learned a lot from the experience, and if we end up doing this again we will make sure these failure modes don't repeat!

Other things we'd change if we have the chance to do it again include:

  • Providing a to-the-second countdown via a widget in the talk room so the speaker & host can see precisely when they're going 'live' in the devroom (and when precisely they're going to be cut in favour of the next talk)
  • Providing a scratch-pad of some kind in the talk room so the host & speaker can track which questions they want to answer, and which they've already answered
  • Keep the questions scoreboard and scratchpad visible to the speaker/host after their Q&A has finished so they can keep answering the questions in the per-talk room, and advertise the per-talk room more effectively.
  • Use Spaces rather than Communities to group the rooms together and automatically provide a structured room directory! (Like this!)
  • Use threads (once they land!) to help structure conversations in the devroom (perhaps these could even replace the hallway rooms?)
  • Make the schedule widgets easier to find, and have more of them around the place
  • Make room directory easier to find.
  • Give the option of recording the video in the per-talk and stands for posterity
  • Provide more tools to stands to help organise demos etc.

So, there you have it. We hope that this shows that it's possible to host successful large-scale conferences on Matrix using an entirely open source stack, and we hope that other events will be inspired to go online via Matrix! We should give a big shout out to HOPE, who independently trailblazed running conferences on Matrix last year and inspired us to make FOSDEM work.

If you want to know more, we also did a talk about FOSDEM-on-Matrix in this month's Open Tech Will Save Us meetup and the Building Massive Virtual Communities on Matrix talk at FOSDEM went into more detail too. Our historical Taking FOSDEM online via Matrix blog has been somewhat overtaken by events but gives further context still.

Finally, huge thanks to FOSDEM for letting Matrix host the social side of the conference. This was a big bet, starting from scratch with our offer to help back in September, and we hope it paid off. Also, thanks to all the folks at Element who bust a gut to pull it together - and to the FOSDEM organisers, who were a real pleasure to work with.

Let's hope that FOSDEM 2022 will be back in person at ULB - but whatever happens, the infrastructure we built this year will be available if ever needed in future.

Taking FOSDEM online via Matrix

2021-01-04 — General — Matthew Hodgson

Imagine you could physically step into your favourite FOSS projects’ chatrooms, mailing lists or forums and talk in person to other community members, contributors or committers? Imagine you could see project leads show off their latest work in front of a packed audience, and then chat and brainstorm with them afterwards (and maybe grab a beer)? Imagine, as a developer, you could suddenly meet a random subset of your users, to hear and understand their joys and woes in person?

This is FOSDEM, Europe’s largest Free and Open Source conference, where every year thousands of people (last year, ~8,500) take over the Solbosch campus of the Université Libre de Bruxelles in Belgium for a weekend and turn it into both a cathedral and bazaar for FOSS, with over 800+ talks organised over 50+ tracks, hundreds of exhibitor stands, and the whole campus generally exploding into a physical manifestation of the Internet. The event is completely non-commercial and volunteer run, and is a truly unique and powerful (if slightly overwhelming!) experience to attend. Ever since we began Matrix in 2014, FOSDEM has been the focal point of our year as we’ve rushed to demonstrate our latest work and catch up with the wider community and sync with other projects.

This year, things are of course different. Thankfully FOSDEM 2020 snuck in a few weeks before the COVID-19 pandemic went viral, but for FOSDEM 2021 on Feb 6/7th the conference will inevitably happen online. When this was announced a few months back, we reached out to FOSDEM to see if we could help: we’d just had a lot of fun helping HOPE go online, and meanwhile a lot of the work that’s gone into Matrix and Element in 2020 has been around large-scale community collaboration due to COVID - particularly thanks to all the development driven by Element’s German Education work. Meanwhile, we obviously love FOSDEM and want it to succeed as much as possible online - and we want to attempt to solve the impossible paradox of faithfully capturing the atmosphere and community of an event which is “online communities, but in person!”... but online.

And so, over the last few weeks we’ve been hard at work with the FOSDEM team to figure out how to make this happen, and we wanted to give an update on how things are shaping up (and to hopefully reassure folks that things are on track, and that devrooms don’t need to make their own plans!).

Firstly, FOSDEM will have its own dedicated Matrix server at (hosted by EMS along with a tonne of Jitsi’s) acting as the social backbone for the event. Matrix is particularly well suited for this, because:

  • We’re an open standard comms protocol with an open network run under a non-profit foundation with loads of open source implementations (including the reference ones): folks can jump on board and participate via their own servers, clients, bridges, bots etc.
  • We provide official bridges through to IRC and XMPP (and most other chat systems), giving as much openness and choice as possible - if folks want to participate via Freenode and XMPP they can!
  • We’re built with large virtual communities in mind (e.g. Mozilla, KDE, Matrix itself) - for instance, we’ve worked a lot on moderation recently.
  • We’ve spent a lot of time improving widgets recently: these give the ability to embed arbitrary webapps into chatrooms - letting you add livestreams, video conferences, schedules, Q&A dashboards etc, augmenting a plain old chatroom into a much richer virtual experience that can hopefully capture the semantics and requirements of an event like FOSDEM.

We’re currently in the middle of setting up the server with a dedicated Element as the default client, but what we’re aiming for is:

  • Attendees can lurk as read-only guests in devrooms without needing to set up accounts (or they can of course use their existing Matrix/IRC/XMPP accounts)
  • Every devroom and track will have its own chatroom, where the audience can hang out and view the livestream of that particular devroom (using the normal FOSDEM video livestream system). There’ll also be a ‘backstage’ room per track for coordination between the devroom organisers and the speakers.
  • The talks themselves will be prerecorded to minimise risk of disaster, but each talk will have a question & answer session at the end which will be a live Jitsi broadcast from the speaker and a host who will relay questions from the devroom.
  • Each talk will have a dedicated room too, where after the official talk slot the audience can pop in and chat to the speaker more informally if they’re available (by text and/or by moderated jitsi). During the talk, this room will act as the ‘stage’ for the speaker & host to watch the livestream and conduct the question & answer session.
  • Every stand will also have its own chatroom and optional jitsi+livestream, as will BOFs or other adhoc events, so folks can get involved both by chat and video, to get as close to the real event as possible (although it’s unlikely we’ll capture the unique atmospheric conditions of K building, which may or may not be a bug ;)
  • There’ll also be a set of official support, social etc rooms - and of course folks can always create their own! Unfortunately folks will have to bring their own beer though :(
  • All of this will be orchestrated by a Matrix bot (which is rapidly taking shape over at, responsible for orchestrating the hundreds of required rooms, setting up the right widgets and permissions, setting up bridges to IRC & XMPP, and keeping everything in sync with the official live FOSDEM schedule.

N.B. This is aspirational, and is all still subject to change, but that said - so far it’s all coming together pretty well, and hopefully our next update will be opening up the rooms and the server so that folks can get comfortable in advance of the event.

Huge thanks go to the FOSDEM team for trusting us to sort out the social/chat layer of FOSDEM 2021 - we will do everything we can to make it as successful and as inclusive as we possibly can! :)

P.S. We need help!

FOSDEM is only a handful of weeks away, and we have our work cut out to bring this all together in time. There are a few areas where we could really do with some help:

  • Folks on XMPP often complain that the Bifröst Matrix<->XMPP bridge doesn’t support MAMs - meaning that if XMPP users lose connection, they lose scrollback. We’re not going to have time to fix this ourselves in time, so this would be a great time for XMPP folks who grok xmpp.js to come get involved and help to ensure the best possible XMPP experience! (Similarly on other bifrost shortcomings).
  • It’d be really nice to be able to render nice schedule widgets for each devroom, and embed the overall schedule in the support rooms etc. The current HTML schedules at and (say) don’t exactly fit - if someone could write a thing which renders them at (say) 2:5 aspect ratio so they can fit nicely down the side of a chatroom then that could be awesome!
  • While we’ll bridge all the official rooms over to Freenode, it’d be even nicer if people could just hop straight into any room on the FOSDEM server (or beyond) via IRC - effectively exposing the whole thing as an IRC network for those who prefer IRC. We have a project to do this: matrix-ircd, but it almost certainly needs more love and polish before it could be used for something as big as this. If you like Rust and know Matrix, please jump in and get involved!
  • If you just want to follow along or help out, then we’ve created a general room for discussion over at It’d be awesome to have as many useful bots & widgets as possible to help things along.
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