ntfy-shutdown@.service

[Unit]
Description=Send a notification on system shutdown
BindsTo=network-online.target
#Wants=network-online.target
After=network-online.target

[Service]
Type=oneshot
Environment=NTFY_URL=https://ntfy.sh
# see https://docs.ntfy.sh/emojis/
Environment=NTFY_TAGS="red_circle"
ExecStart=/bin/true
RemainAfterExit=true
ExecStop=/usr/bin/sh -c "curl -H \"Tags: $NTFY_TAGS\" -H \"Firebase: no\" -d \"%H is shutting down\" $NTFY_URL/%i"

[Install]
WantedBy=default.target