Tested on shairport-sync 3.3.8, currently available on mobian/bookworm.

The process is pretty similar to what you’d do on a Raspberry Pi.

Install and configure shairport-sync

apt install shairport-sync

Edit /etc/shairport-sync.conf to set the backend to pulseaudio with:

output_backend = "pa";

Create a systemd user service and start it:

mkdir ~/.config/systemd/user

Edit ~/.config/systemd/user/shairport-sync.service and add:

[Unit]
Description=Shairport Sync - AirPlay Audio Receiver

[Service]
ExecStart=/usr/bin/shairport-sync
Restart=on-failure

[Install]
WantedBy=default.target

Enable and start the new service:

systemctl --user enable --now shairport-sync

Enable default user (mobian) lingering, so the speaker runs even when you haven’t logged in:

sudo loginctl enable-linger mobian