diff --git a/deploy/thermograph-dev.service b/deploy/thermograph-dev.service
new file mode 100644
index 0000000..30d22e2
--- /dev/null
+++ b/deploy/thermograph-dev.service
@@ -0,0 +1,20 @@
+# systemd --user unit for the Thermograph LAN dev server.
+# Installed by deploy/deploy-dev.sh into ~/.config/systemd/user/ with the
+# @PLACEHOLDER@ tokens substituted for this machine's paths/port.
+# Runs sudo-free as your own user; linger keeps it up across logout/reboot.
+[Unit]
+Description=Thermograph (dev, LAN) - FastAPI/uvicorn
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=exec
+WorkingDirectory=@APP_DIR@/backend
+Environment=THERMOGRAPH_BASE=@BASE@
+# Bind all interfaces so other devices on the LAN (e.g. your phone) can reach it.
+ExecStart=@APP_DIR@/.venv/bin/uvicorn app:app --host 0.0.0.0 --port @PORT@
+Restart=on-failure
+RestartSec=2
+
+[Install]
+WantedBy=default.target