Matrix
From Organic Design wiki
Docker installation
First generate a default configuration file for your domain as follows, this will automatically pull the necessary containers as well.
docker run -it --rm --mount type=volume,src=synapse-data,dst=/data -e SYNAPSE_SERVER_NAME=organicdesign.co.nz -e SYNAPSE_REPORT_STATS=yes matrixdotorg/synapse:latest generate
This will create a new volume with your persistent configuration file in it in /var/lib/docker/volumes/synapse-data/_data/homeserver.yaml
Next, run the container on a local-only port so that a reverse proxy can be made from your web-server to handle the HTTPS side of things (not described here).
docker run -d --name synapse --mount type=volume,src=synapse-data,dst=/data -p 127.0.0.1:18008:8008 matrixdotorg/synapse:latest