diff --git a/hosts/profiles/matrix/register-user.sh b/hosts/profiles/matrix/register-user.sh
new file mode 100755
index 0000000..0530d3c
--- /dev/null
+++ b/hosts/profiles/matrix/register-user.sh
@@ -0,0 +1,24 @@
+#!/usr/bin/env nix-shell
+#! nix-shell -i bash -p matrix-synapse
+
+set -euo pipefail
+
+SYNAPSE_CONFIG="/run/agenix/synapse-config"
+
+if [ $# -eq 0 ]; then
+  echo "Usage: register-user.sh -u USERNAME -p PASSWORD [--no-admin | -a]"
+  echo "Example: register-user.sh -u alice -p PLEASECHANGETHISPASSWORD --no-admin"
+  exit 1
+fi
+
+SHARED_SECRET=$(sudo sed -n 's/.*registration_shared_secret:[[:space:]]*"\?\([^"]*\)"\?.*/\1/p' "$SYNAPSE_CONFIG")
+
+if [ -z "$SHARED_SECRET" ]; then
+  echo "Error: Could not extract registration_shared_secret from $SYNAPSE_CONFIG"
+  exit 1
+fi
+
+register_new_matrix_user \
+  -k "$SHARED_SECRET" \
+  "$@" \
+  http://localhost:8448