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Matrix is an ambitious new ecosystem for open federated instant messaging and VoIP. It consists of servers, clients and bridge software to connect to existing messaging solutions like IRC.

We also have a matrix channel for Arch! Come join us at

For a list of Matrix clients, see the Matrix Clients section of List of Applications.


The reference server implementation Synapse is available in the community repository as matrix-synapse. The community package creates a synapse user.


After installation, a configuration file needs to be generated. It should be readable by the synapse user:

$ cd /etc/synapse
$ sudo -u synapse python -m \
  --server-name \
  --config-path /etc/synapse/homeserver.yaml \
  --generate-config \

Note that this will generate corresponding SSL keys and self-signed certificates for the specified server name. You have to regenerate those if you change the server name.


The synapse.service systemd service is included in the matrix-synapse package. It will start the synapse server as user synapse and use the configuration file /etc/synapse/homeserver.yaml.

User management

You need at least one user on your fresh synapse server. You may create one as your normal non-root user with the command

$ register_new_matrix_user -c /etc/synapse/homeserver.yaml

or using one of the matrix clients, for example element-desktop, or the purple-matrix-gitAUR plug-in for libpurple.

Spider Webcrawler

To enable the webcrawler, for server generated link previews, the additional packages python-lxml and python-netaddr have to be installed. After that the config option url_preview_enabled: True can be set in your homeserver.yaml. To prevent the synapse server from issuing arbitrary GET requests to internal hosts the url_preview_ip_range_blacklist: has to be set.

Warning: There are no defaults! By default the synapse server can crawl all your internal hosts.

There are some examples that can be uncommented. Add your local IP ranges to that list to prevent the synapse server from trying to crawl them. After changing the homeserver.yaml the service has to be restarted.