Some technical words to explain the project.

We usually present SàT as a multipurpose, multi frontend, free (libre) and decentralised communication tool... Let us explain what we mean:

Based on the powerful XMPP standard, SàT can obviously be used for instant messaging and much more! Blogging and microblogging, file sharing, games are other possible usage.... Using gateways, you can also communicate with other networks like IRC or StatusNet. It is also possible to redirect your XMPP messages to your email address, or to send an email that would be delivered on XMPP. The "X" of XMPP stands for eXtensible: our features list is also extensible! Check the specifications page for a current status of what we've been doing.


Multi frontend

SàT has been developped since the beginning with an idea in mind: it should be useable from the command line, with a console or desktop interface, from a web browser. The backend of the software manages the communication with your XMPP server and does most of the processing. On top of that, you are free to use the frontend of your choice. If you would like to help the project, a great thing would be to develop a new frontend so don't hesitate to contact us!



We exclusively use and develop free and open-source software. It is not only free for you to get and run it, but you can also analyse it, modify it or redistribute it. Since this is enough to free a program but not the person who uses it, we wrote a social contract - a moral engagement with the user - that is also mentioned in the statutes of the association.

Social contract


This is the most complicated aspect to understand, yet a crucial one. Being based on XMPP, SàT is immediately decentralised (federated). But what does it mean? To get this point, we need to imagine the Internet as a set of layers. To make it easier, let's say there are only two layers: the physical and the logical one. On the physical layer, you are directly connected to your service provider, and indirectly to all the rest of the world.

On the logical layer, you are directly connected to your usual "social network", and since it's centralised, all its users are directly connected to it: it can access and own all the data, it can unilaterally decide to censor or exclude a user. It has too much power.

Centralised communication system on top of the physical layer - note that one user on the right who refuses to use such a system.

Now what if your usual "social network" is decentralised? The main difference is that there's not a single entity to manage all the connections and all the data, but a lot of them. All the users are connected to the same network, but each of them can decide which server they want to connect to. As a result, the data and the network administration's tasks are shared between all the servers. Is it possible to do that on the Internet? Yes, this is how the email works! That's decentralisation.

Decentralised communication system on top the physical layer - the user on the right is still resisting.

Now what if you don't trust anybody? Then you are free to host your own server at home, via an association or in your work office. Is this possible too?! Yes, this is also how the email works! And this is what we did for our server and without asking anybody's permission - the XMPP interdomain federation makes it possible.

Decentralised communication system with self-hosting ability - the dot on the right is still an Internet user, but for the communication service it's both a user and a server.

So... in a nutshell: decentralisation is like how the email works. There are many servers, you can use the one you want and if you want to help the decentralisation, you can also add a new server by yourself. It requires some technical knowledge but it doesn't cost much and it allows more freedom. Feel free to contact us if you need some details!

Note: decentralisation, federation, distribution... these terms are not strictly defined. To debate about that is not the goal of this page, but we recommend you the reading of this article: Beyond distributed and decentralized: what is a federated network? It's not XMPP-specific but it's a good start.

Using a standard protocol is a key point: it's robust, widely used, tested and well documented. Every change is discussed publicly, there are debates on the best way to achieve goals and the XSF is the guarantor of the evolution and stability of the protocol.

As a consequence, SàT communicates with other XMPP projects and the way we "talk" together is fully documented. For the user, this means you can switch from one XMPP client to another using the same account. This is taking the opposite direction to some proprietary and commercial networks which tend to lock their users up. Open your borders!


Since its beginning, the SàT project was made with other platforms in mind. It's only available on GNU/Linux so far (except of course Libervia, the web interface, which is available from any modern browser), but other platforms are planned.