Chaos Computer Club - recent events feed

With *Beyond Instant Messaging: Matrix in the Public Sector* last year, we presented FITKO and the German Federal Ministry of the Interior joining efforts to pilot a Matrix-based next-generation communication infrastructure for digital government services, with the goal to showcase end-to-end encryption, great usability and machine-readable communication between citizens and public authorities. Lets take another look at the project, what we have done since and what else there is to come for *reaching the German Government via Matrix* Visit our projet page for more details https://gitlab.opencode.de/fitko/matrix-g2x (currently in German) This project is part of a larger target architecture, see the earlier talk "Consolidating Germany’s administrative communication: Towards a joint Matrix-based architecture" by my colleague Dominik Braun. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/Q3LKTY/

Can Matrix compete with Big Tech? That remains an open question - but the market conditions in Europe have never been more favorable to sovereign, European software solutions. So how do we build commercially sound companies based on Matrix? This talk will focus on real-world use cases, showcase features built for public-sector customers, explore viable business models, and share hard-earned lessons from bringing Matrix to market. Agenda: 1. Why Meedio? Why Matrix? 2. Going open source - choosing the right business model 3. From proprietary to Matrix - evolution timeline 4. Technical integration journey - architecture overview 4.1 Meedio solutions 4.2 Meedio components infrastructure 4.3 MSC's used 5. KBV-Certified consultations - when Signal is not enough 6. Scaling federation and predictability 6.1 Vanilla Synapse 6.2 Desperation phase 6.3 Vanilla Synapse to ESS Pro 6.4 Synapse Pro (ESS Pro) 7. Demo Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/GX397V/

In this talk we will introduce Synapse Pro, the Matrix server for professional environments from Element. Synapse Pro is built to support professional Matrix deployments in terms of scalability, efficiency and high availability. It comes in two flavours, Synapse Pro for Small Hosts and Synapse Pro for Large Hosts. The Small Hosts solution introduces multi-tenancy capabilities in order to host plenty of small Matrix servers in a resource-saving and cost-efficient way. The Large Hosts solution enhances Synapse with more efficient implementations of its subsystems and provides auto-scaling as well as high availability capabilities. This talk will give you detailed insights on both solutions and their benefits for Element customers. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/AETNRS/

The BundesMessenger is the soverein communication solution for the German government and armed forces. Developed to be robust, secure and interconnected it serves as the basis for collaboration in the public sector. With a sharp focus on user experience, an uncompromised commitment to free and open-source software and state-of-the-art deployment of cloud technologies, it brings a high-quality messenger to firefighters, soldiers and office workers. Want to know what makes the BundesMessenger quite a special piece of software? Is it better than fax? And will it shut up after I call it a day? Join the talk to find out! Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/9HKYHA/

In many parts of the world, especially across Africa, software cannot assume a stable internet connection. From rural communities to field agents working in transit or enforcement, the reality is simple: offline is the default, and sync is a luxury. In this talk, we’ll explore how to build offline-first applications using Python — apps that work gracefully when the network doesn’t. Drawing from real-world civic and infrastructure projects scenarios in Nigeria, I’ll walk through techniques to queue, cache, and sync data locally, using tools like SQLite, Redis, Celery, and FastAPI. We’ll explore design patterns that prevent data loss, improve user experience, and simplify reconciliation once connectivity is restored. Whether you’re building field data tools, mobile dashboards, or lightweight IoT integrations, this session will equip you with the mindset and technical building blocks to ensure your Python applications stay resilient — no matter the network conditions. about this event: https://talks.python-summit.ch/sps25/talk/PBVN3P/

On July 15, 2025, Germany’s statutory health insurance funds will introduce the Matrix-based instant messaging service TI-M (Telematikinfrastruktur Messenger) into their electronic patient record (ePA) apps. This marks a significant milestone, as Matrix-based messengers will become potentially available to 74 million insured individuals across Germany. This talk will provide an overview of the nationwide rollout, highlighting the technical and organizational challenges faced during the development and operation of TI-M, including interoperability, security, and scalability within the highly regulated healthcare environment. We will present up-to-date usage data and insights on user adoption, reflecting the initial impact and acceptance of TI-M among patients and healthcare professionals. Finally, the session will offer an outlook on the future of secure, decentralized communication in the German healthcare system, discussing opportunities for further integration, innovation, and the broader implications for digital health infrastructure. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/SHDUM3/

Element Call, the flagship MatrixRTC application by Element, is shaping the future of secure, federated calling. As the successor to the traditional call system in Element apps, it now powers large-scale, end-to-end encrypted (E2EE) group calls with improved reliability and seamless federation support. This talk follows up on last year’s introduction of Element Call, showcasing a year of rapid innovation — from new media transport mechanisms to enhanced mobile features — all aimed at making secure communication effortless and intuitive. Last year, we introduced Element Call as the next-generation MatrixRTC solution for calling over Matrix. In 2025, it’s no longer just a promising beta—it’s the default call experience in Element apps and a key pillar of the Matrix ecosystem. This talk will cover the evolution of Element Call over the past year, including: - MatrixRTC in production: how Element Call is now the core calling experience in Element apps, replacing the legacy call stack. - Scalable E2EE group calls: supporting large encrypted calls with significantly improved reliability and federation support. - New transport layer: leveraging to-device messages for secure and robust end-to-end media encryption across calls. - A new MatrixRTC Transport using a Multi-SFU approach - Ease of use: new UX features like emoji reactions and background blurring. - Mobile-first features: introducing Handset Mode for more natural audio on mobile devices. Whether you're a Matrix developer, community member, or integrator, this session will give you an inside look at where MatrixRTC is headed and how to build on top of it. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/BQZHAH/

Are you writing nested loops when solving coding challenges? Discover how Python's functional programming toolbox can transform your problem-solving approach. We'll explore functional programming principles through the lens of Advent of Code puzzles, learning to think in streams of data rather than step-by-step instructions. We’ll explore some essential bits from `itertools`, `functools`, and `operator` modules, aiming to write more expressive, debuggable code. Starting with pure functions and lazy evaluation, we'll build up to solving real AoC problems using techniques like: `itertools.pairwise()` for sequence comparisons, `functools.reduce()` for data aggregation, `operator.itemgetter()` for elegant sorting, Generator expressions for memory-efficient processing. Through some puzzles from various years, we’ll see how functional approaches often lead to more concise solutions that closely mirror the problem description. We'll compare imperative vs functional solutions, highlighting pros and cons of both approaches. Whether you're preparing for coding interviews, tackling AoC, or just want to expand your Python toolkit, you'll leave with a couple more ideas for writing cleaner, more Pythonic code - no external dependencies required. about this event: https://talks.python-summit.ch/sps25/talk/PA7988/

Nobody likes fax machines, yet everyone still uses them – that's the reality in German hospitals. Since 2019, Famedly has been challenging this status quo. With our TI Messenger, built on the Matrix protocol, we've created a secure and decentralized alternative. Learn how we're using and extending Matrix to modernize communication in the German healthcare system. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/BBXTLT/

Looking for more resilience and sovereignty, the European Commission has been running a trial Matrix deployment. This talk will present some of the work done. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/MDHBPY/

Our project's main goal was to fill a gap by developing a telephony bridge that natively integrates XiVO enterprise telephony (based on SIP) within the alternative and open-source Matrix/Element ecosystem. Our focus with this bridge is to offer a credible and high-performing alternative to dominant proprietary solutions, such as Teams and its "Telephony System" licenses. XiVO SIP bridge project presented a significant development challenge, underscoring its disruptive and creative nature. This wasn't a simple assembly of existing technologies, but an engineering effort to bridge two fundamentally different protocols: WebRTC used by Matrix ecosystem and SIP from the IP telephony world. This bridge (built as a Synapse module for now) allows Element to integrate enterprise telephony capabilities provided by XiVO, open source IPBX using Asterisk. The integration approach between XiVO telephony and the Matrix protocol involved designing specific gateways and APIs for interoperability of identities (XiVO user vs. Matrix user, i.e., phone number vs. mxID) and telephony features (answer, hang up, hold, etc.) directly within the Element Web interface. The impacts, and outcomes of this successful bridge project are significant. It allows a substantial reduction in communication costs for businesses by eliminating proprietary telephony licenses, all within a single, open-source unified communication tool. It also creates value for the French and European open-source ecosystems. In short, the XiVO/Element bridge is not a mere improvement on existing solutions but a disruptive proposal that creates a "bridge" between the world of traditional telephony and modern unified communications. It, nevertheless, required solving complex problems: - How do you reconcile different protocols and semantics? The SIP protocol manages specific states and signals (e.g., INVITE for ringing, HOLD for putting a call on hold) that have no direct equivalent in the Matrix protocol. The difficulty lies in designing a mechanism capable of interpreting these SIP events, translating them into relevant Matrix events, and vice versa, to maintain a consistent user experience. - The bridge must be able to robustly track the state of these sessions and ensure that actions performed on one side (for example, rejecting a call in the web interface) are correctly executed and reflected on the XiVO PBX in SIP. A failure in this IPBX/Matrix synchronization could lead to inconsistencies (e.g., a call that still appears active on one side even though it has ended on the other). The idea is to use this presentation to share our progress on this bridge, its integration into our soft-fork of Element (xivo-connect) with a supporting demo, and our expectations to integrate it into Tchap (French gov soft-fork of Element). We also want to share our successes and ideas for the future to benefit the entire Matrix community. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/CYXHGK/

Last year, we introduced NeoToolSuite, Nordeck’s productivity suite of Matrix widgets designed for efficient collaboration and communication. This year, our focus shifts to our flagship product: NeoBoard Standalone. This real-time collaborative whiteboard matrix client has evolved through continuous development and iteration and now it features an immersive infinite canvas that redefines what’s possible for open-source productivity and creative tools. Join us for a tour of NeoBoard’s latest features and share our vision for the future of real-time collaboration, powered by the Matrix protocol. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/KHM9ZY/

European healthcare communication is at a turning point. Fragmented national systems are reaching their limits, while the need for interoperable, secure, and user-friendly digital spaces across borders continues to grow. This talk explores how the open-source Matrix protocol has become a strategic foundation for secure messaging in healthcare — powering derived solutions like TI Messenger and CGM Messenger. Our approach highlights not only the technology itself but also the importance of collaboration with the open-source community, especially through our partnership with Element, to drive innovation, scalability, and trust. Key themes include deep integration into primary systems, the use of headless clients, and tackling challenges around usability, eID identity models, and technical complexity. We argue that while Matrix alone is not the silver bullet for interoperability, it provides the missing bridge between siloed infrastructures and the vision of a unified European Health Space — rooted in open standards and coordinated implementation. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/GDWSJR/

The German public administration aims to consolidate its disparate solutions for G2C and G2B communications and transition to a unified yet decentralized Matrix-based infrastructure. In this talk we will dive into this new federal infrastructure’s target architecture and explore its key requirements, drivers and architecture decisions – including the crucial choice of Matrix as the E2EE communications layer. We further share key learnings from the accompanying political process and reflect on the challenges ahead in constructing, negotiating and implementing transition pathways to achieve change in the complex brownfield-environment of Germany’s administrative IT. Note: If you want something more hands-on, take a deep dive into our technical pilot project for Matrix-based G2C-communication in Germany by attending our second talk at this year's Matrix conference: https://cfp.2025.matrix.org/matrix-conf-2025/talk/Q3LKTY/ Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/L8LXQU/

Why should you, as a Python developer, learn Rust? In this talk, we will explore Rust's compelling answers to this question. Rust offers guaranteed type safety and memory safety without a garbage collector, "fearless concurrency", and incredible performance. We will look into some of Rust's most distinctive features from a Python perspective, including its strict compiler, the ownership and borrowing system, null safety via `Option<T>`, and explicit mutability. We will discover how Rust eliminates common runtime errors at compile time, and additionally, how understanding the concepts behind Rust's safety features can sharpen your Python skills, helping to write more robust and reliable code. By the end of the talk, you'll understand Rust's core value proposition and how its paradigms can benefit you, whether you are writing Python, Rust, or any other language. about this event: https://talks.python-summit.ch/sps25/talk/WDJ3WU/

Bytecode, the internal language of instructions used by the interpreter is something that perhaps most Python developers have heard about, but few have dug into. This talk will try to explain the idea behind bytecode and how it works. We will see how to extract bytecode from functions - with `dis` module, and from `.pyc` files (and what is the idea of `__pycache__` directories). Then, the other way around: we’ll check the possibility of building new functions with raw bytes in runtime. about this event: https://talks.python-summit.ch/sps25/talk/9NWPB9/

In this presentation, we will examine processes within the German healthcare system and explore the underlying structural challenges that make intersectoral communication so difficult. We will discuss why Matrix is the ideal protocol for the foundation of this infrastructure and explain how we build upon the Matrix specification to meet healthcare-specific requirements. Special insights will be shared regarding the challenges and lessons learned during the implementation of the TI-Messenger in Germany’s healthcare system. The presentation will outline the different stages of development and highlight specific use cases that demonstrably improve the quality of care. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/QGQX9L/

Twenty seconds is a long time when someone can’t breathe. At ESA´s LUNA Analog Facility we turned that reality into a design constraint: a moonwalk emergency with voice cut by design, Matrix/Element carrying clinical guidance across a built-in one-way delay. We tested two styles of instant messaging, open free-text versus a tiny, structured grammar, to coordinate assessment, treatment, and evacuation over a delay-tolerant (store-and-forward) network. The first signals are clear: structure lowers cognitive load and keeps decisions moving even when replies arrive “late.” We’ll share what worked, what didn’t, and how the same patterns translate to Earth during hospital IT outages. With publications in progress, this talk focuses on early signals and the method itself, showing how Matrix enabled care under delay and how small changes could improve resilience. We start with a quick introduction of the LUNA Analog Facility, why a Moon-like regolith hall, ground segment, and “moonwalk” simulation are ideal for testing communications under stress, then walk through our method: we intentionally disabled voice, enforced ~20-second one-way delay, and coordinated clinical care entirely over Matrix/Element on a delay-tolerant (store-and-forward) link. You’ll see how we compared open free-text with a compact, structured chat grammar and which small conventions, clear end-markers, role tags, micro-acks, bounded message size, simple priority cues, reliably reduced ping-pong and cognitive load while keeping treatment safe. From there, we look beyond the Moon: practical takeaways for Earth hospitals facing outages (offline-first clients, lightweight message grammar for critical steps, prebuilt templates), and EVA-oriented tweaks that seem promising, such as lightweight clinical field sets and mobile/edge Matrix homeservers with opportunistic federation under delay. Publications are in progress; this session focuses on the method and early signals and what they imply for building resilient, message-driven care when “real-time” isn’t guaranteed. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/PUUXDL/

MLS and Matrix don't mix well. But why is that and what can we do about it? Since I got to touch that area a bit, I'll try to give some answers, but don't expect solutions. We will be looking how MLS and Matrix work internally, how a tree is a DAG but a DAG not a tree and maybe we will have some glorious idea or get frustrated. No promises! Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/Z9B878/

In this talk, we’ll take you through the real-world journey of developing and approving a TI-Messenger - a secure, interoperable messaging application built on top of the Matrix protocol for use within Germany’s healthcare system. What began as am idea soon grew into a tightly regulated, multi-stakeholder project, with high demands on privacy, trust, and compliance. This session is less about features and more about transformation. It’s a case study of how we shaped a Matrix-based messenger to meet the strict security, interoperability, and governance requirements defined by the gematik specification, and how that shaped our development process in return. Unlike general-purpose Matrix clients, the TI-Messenger is deeply constrained by legal frameworks, security audits, and standardized certification making the path from concept to approval full of unique challenges. We’ll reflect on what we learned about applying Matrix in high-trust environments, what we would do differently, and how our experience could inform similar efforts elsewhere. Whether you’re working in the public sector, healthcare, or simply curious how Matrix can scale to more regulated use cases, this talk offers an inside look at what it takes to make Matrix meet mission-critical standards. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/YMCDE7/

For decades, government agencies have relied on proprietary, siloed communication systems. Today, several Swedish initiatives are exploring new paths forward. First, we will provide details on the latest developments within SAFOS, a service designed to establish a potential national standard for secure messaging, video conferencing, and real-time collaboration. Second, we will share insights from eSam — a voluntary collaboration between public agencies — where a multi-agency task force is evaluating options for a common, open, and federated protocol for real-time communication. We will discuss our evaluation criteria, the challenges, and the potential of solutions such as Matrix to foster true interoperability, decentralization, and robust security for Sweden's public administration. Join us to learn how Försäkringskassan and eSam are exploring ways to build a future-proof communication infrastructure based on openness and collaboration. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/DZBGLP/

Code review is a central part of everyday developer jobs. The motivation to create this talk was a quote: “The most important superpower of a developer is complaining about everybody else's code.” In this talk, I’ll explain my approach to better code review. Sometimes, it’s hard to convince a colleague about change or don’t change some lines of code. In my talk I would like to cover some best practices from my software engineering experience about efficient and honest code review. How to create a culture of perfect code review. How to apply automatic tools to improve code review routine of repetitive comments or suggestions. How to write/or reuse coding style guides for your team to reduce the time spent arguing about naming conventions and different styles. What needs to be automated and what needs to be not automated during code review? The key role of patterns that can be reusable is not to confuse colleagues. about this event: https://talks.python-summit.ch/sps25/talk/ESM3K7/

With the TI-Messenger, built on the Matrix protocol, Famedly has enabled secure and interoperable communication across the German healthcare system, from hospitals to pharmacies. Adoption is growing rapidly, with millions of potential users on the horizon. In this opening talk, we’ll look back at TIM’s journey so far, highlight its impact and adoption, and then take a step beyond healthcare into the government. We’ll also give a glimpse into MLS and how it will strengthen security and interoperability for all Matrix-based applications in the future. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/XTTQ3R/

Since 2024, the Swiss federal government has been obliged by the new EMOTA law to publish all its software under open source licenses. This new 'Federal Act on the Use of Electronic Means to Conduct Official Tasks' (EMOTA) has had an impact on IT procurement and open source activities in Switzerland. By encouraging the creation of open source communities, the law reduces vendor lock-in and strengthens digital sovereignty. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/KCKEYJ/

[matrix] as an end-to-end encrypted communication standard has its flaws. Flaws in privacy, flaws in complexity. With the standard of Messaging Layer Security (MLS), the [matrix] ecosystem has the opportunity to address old flaws, rethink room state and increase interoperability. In this talk, I will provide a beginner's guide on challenges of [matrix] 3.0. > Messaging Layer Security (RFC 9420, MLS) is a modern layer for end-to-end encrypted group messaging providing Forward Secrecy (PFS) and Post-Compromise Security (PCS). MLS further provides performance that’s logarithmic in the group size, an easy migration to post-quantum security, and is a rigorously analyzed protocol. This talk will discuss the opportunities and challenges offered by MSC4256 proposing a way to integrate MLS into [matrix] rooms. As a guidance, I will focus on the following questions : - Which advantages does MLS feature over Olm ? - Which tradeoffs can we accept with an interoperable encryption standard ? - How can we keep a federated ecosystem working with an encryption standard not meant for complete distribution ? - How can we ensure to keep sync of MLS state and [matrix] room state ? - How can we incrementally migrate an ecosystem to another encryption standard ? The entire topic of MLS is obviously too big for a single talk. Many of the open questions may only be discussed briefly. The aim of this talk is not to present outstanding solutions like a miracle but rather to inform about the current state of the specification, the ecosystem and next steps. Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/BAKSEA/

Sometimes getting an approximate answer is super good enough. How do you check for duplicates, count unique users, or track item popularity when your dataset won’t fit in memory? Enter probabilistic data structures like Bloom filters, Count-Min Sketches, and HyperLogLog! This talk introduces these powerful tools, demonstrates simple implementations in Python, and gives you ideas on when to use them. Walk away ready to apply these techniques in your own projects - no advanced math required. about this event: https://talks.python-summit.ch/sps25/talk/QBXDUQ/

A welcome message and useful information from the organisers. You will also find useful information on our [website](https://www.python-summit.ch/). Or feel free to ask any member of staff if you have a question. about this event: https://talks.python-summit.ch/sps25/talk/LL3K3L/

As project lead of Matrix, Matthew gives a snapshot of where the project is at. Highlights should include: * Overview of recent high-profile Matrix deployments and uptake * Overview of the recent major projects to fix state resets and improve decentralisation reliability * Overview of making Matrix a safer place via improved Trust & Safety work * Progress on Matrix 2.0 MSCs (Next Gen Auth, Sliding Sync, MatrixRTC) and uptake * Progress on Olm/Megolm improvements (history sharing, TOFU, invisible crypto, etc) * Progress on Next-generation encryption work ...and more! Licensed to the public under https://creativecommons.org/licenses/by-sa/4.0/ about this event: https://cfp.2025.matrix.org/matrix-conf-2025/talk/8PEMJB/