diff --git a/buzz/buzz-listener.service b/buzz/buzz-listener.service
new file mode 100644
index 0000000..9c91a37
--- /dev/null
+++ b/buzz/buzz-listener.service
@@ -0,0 +1,13 @@
+[Unit]
+Description=Buzz relay listener (zai presence + message spool)
+After=network-online.target docker.service
+
+[Service]
+User=opc
+WorkingDirectory=/opt/buzz-listener
+ExecStart=/usr/local/bin/node /opt/buzz-listener/listener-raw.mjs
+Restart=always
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target
diff --git a/buzz/ws-listener/listener-raw.mjs b/buzz/ws-listener/listener-raw.mjs
index 531d46a..cdacbe3 100644
--- a/buzz/ws-listener/listener-raw.mjs
+++ b/buzz/ws-listener/listener-raw.mjs
@@ -3,6 +3,7 @@
 // On a matching kind-9 event from another pubkey: spool to inbox, exit 0.
 import { finalizeEvent, getPublicKey } from 'nostr-tools/pure'
 import fs from 'node:fs'
+import { execFileSync } from 'node:child_process'
 
 const RELAY = 'wss://ch4t.buzz'
 const CH = 'cc2aac17-af28-47ba-8563-c2cbb8633084'
@@ -71,3 +72,21 @@ ws.onclose = () => { console.error('ws closed'); process.exit(2) }
 ws.onerror = () => {}
 
 setTimeout(() => { console.error('lifetime elapsed'); process.exit(3) }, MAX_LIFETIME)
+
+// Presence heartbeat: relay TTL is 180s, contract says refresh every 60s.
+// Listener alive = zai "online"; backend dead = offline within 3 minutes.
+const BUZZ_CLI = '/usr/local/bin/buzz'
+const heartbeat = () => {
+  try {
+    execFileSync(BUZZ_CLI, ['users', 'set-presence', '--status', 'online'], {
+      env: { ...process.env, BUZZ_RELAY_URL: 'https://ch4t.buzz', BUZZ_PRIVATE_KEY: keyText.match(/SECRET:\s*(\S+)/)[1] },
+      stdio: 'ignore',
+      timeout: 20000,
+    })
+    console.error('presence heartbeat ok')
+  } catch (e) {
+    console.error('presence heartbeat failed:', String(e).slice(0, 120))
+  }
+}
+heartbeat()
+setInterval(heartbeat, 60 * 1000)
diff --git a/buzz/ws-listener/package-lock.json b/buzz/ws-listener/package-lock.json
new file mode 100644
index 0000000..2288e74
--- /dev/null
+++ b/buzz/ws-listener/package-lock.json
@@ -0,0 +1,120 @@
+{
+  "name": "ws-listener",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "ws-listener",
+      "version": "1.0.0",
+      "license": "ISC",
+      "dependencies": {
+        "nostr-tools": "^2.25.2"
+      }
+    },
+    "node_modules/@noble/ciphers": {
+      "version": "2.1.1",
+      "resolved": "https://registry.npmjs.org/@noble/ciphers/-/ciphers-2.1.1.tgz",
+      "integrity": "sha512-bysYuiVfhxNJuldNXlFEitTVdNnYUc+XNJZd7Qm2a5j1vZHgY+fazadNFWFaMK/2vye0JVlxV3gHmC0WDfAOQw==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 20.19.0"
+      },
+      "funding": {
+        "url": "https://paulmillr.com/funding/"
+      }
+    },
+    "node_modules/@noble/curves": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/@noble/curves/-/curves-2.0.1.tgz",
+      "integrity": "sha512-vs1Az2OOTBiP4q0pwjW5aF0xp9n4MxVrmkFBxc6EKZc6ddYx5gaZiAsZoq0uRRXWbi3AT/sBqn05eRPtn1JCPw==",
+      "license": "MIT",
+      "dependencies": {
+        "@noble/hashes": "2.0.1"
+      },
+      "engines": {
+        "node": ">= 20.19.0"
+      },
+      "funding": {
+        "url": "https://paulmillr.com/funding/"
+      }
+    },
+    "node_modules/@noble/hashes": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/@noble/hashes/-/hashes-2.0.1.tgz",
+      "integrity": "sha512-XlOlEbQcE9fmuXxrVTXCTlG2nlRXa9Rj3rr5Ue/+tX+nmkgbX720YHh0VR3hBF9xDvwnb8D2shVGOwNx+ulArw==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 20.19.0"
+      },
+      "funding": {
+        "url": "https://paulmillr.com/funding/"
+      }
+    },
+    "node_modules/@scure/base": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/@scure/base/-/base-2.0.0.tgz",
+      "integrity": "sha512-3E1kpuZginKkek01ovG8krQ0Z44E3DHPjc5S2rjJw9lZn3KSQOs8S7wqikF/AH7iRanHypj85uGyxk0XAyC37w==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://paulmillr.com/funding/"
+      }
+    },
+    "node_modules/@scure/bip32": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/@scure/bip32/-/bip32-2.0.1.tgz",
+      "integrity": "sha512-4Md1NI5BzoVP+bhyJaY3K6yMesEFzNS1sE/cP+9nuvE7p/b0kx9XbpDHHFl8dHtufcbdHRUUQdRqLIPHN/s7yA==",
+      "license": "MIT",
+      "dependencies": {
+        "@noble/curves": "2.0.1",
+        "@noble/hashes": "2.0.1",
+        "@scure/base": "2.0.0"
+      },
+      "funding": {
+        "url": "https://paulmillr.com/funding/"
+      }
+    },
+    "node_modules/@scure/bip39": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/@scure/bip39/-/bip39-2.0.1.tgz",
+      "integrity": "sha512-PsxdFj/d2AcJcZDX1FXN3dDgitDDTmwf78rKZq1a6c1P1Nan1X/Sxc7667zU3U+AN60g7SxxP0YCVw2H/hBycg==",
+      "license": "MIT",
+      "dependencies": {
+        "@noble/hashes": "2.0.1",
+        "@scure/base": "2.0.0"
+      },
+      "funding": {
+        "url": "https://paulmillr.com/funding/"
+      }
+    },
+    "node_modules/nostr-tools": {
+      "version": "2.25.2",
+      "resolved": "https://registry.npmjs.org/nostr-tools/-/nostr-tools-2.25.2.tgz",
+      "integrity": "sha512-7JAx+brEPmqGz1yzaK9MOxvis/Nl1B38j9hVsBSRDMRmxk5XSc0+5LlPEYbzeiUyk41RURBDcfuMzmaT754HAg==",
+      "license": "Unlicense",
+      "dependencies": {
+        "@noble/ciphers": "2.1.1",
+        "@noble/curves": "2.0.1",
+        "@noble/hashes": "2.0.1",
+        "@scure/base": "2.0.0",
+        "@scure/bip32": "2.0.1",
+        "@scure/bip39": "2.0.1",
+        "nostr-wasm": "0.1.0"
+      },
+      "peerDependencies": {
+        "typescript": ">=5.0.0"
+      },
+      "peerDependenciesMeta": {
+        "typescript": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/nostr-wasm": {
+      "version": "0.1.0",
+      "resolved": "https://registry.npmjs.org/nostr-wasm/-/nostr-wasm-0.1.0.tgz",
+      "integrity": "sha512-78BTryCLcLYv96ONU8Ws3Q1JzjlAt+43pWQhIl86xZmWeegYCNLPml7yQ+gG3vR6V5h4XGj+TxO+SS5dsThQIA==",
+      "license": "MIT"
+    }
+  }
+}