diff --git a/muxplex/frontend/app.js b/muxplex/frontend/app.js
index 6687151..5821e1d 100644
--- a/muxplex/frontend/app.js
+++ b/muxplex/frontend/app.js
@@ -1184,6 +1184,57 @@ function buildSources(settings) {
   return sources;
 }
 
+/**
+ * Build a single remote instance row element with URL input, name input, and remove button.
+ * @param {string} url - remote instance URL
+ * @param {string} name - remote instance display name
+ * @returns {HTMLDivElement}
+ */
+function _buildRemoteInstanceRow(url, name) {
+  var row = document.createElement('div');
+  row.className = 'settings-remote-row';
+  var urlInput = document.createElement('input');
+  urlInput.type = 'text';
+  urlInput.className = 'settings-remote-url';
+  urlInput.placeholder = 'http://192.168.1.x:8000';
+  urlInput.value = url || '';
+  var nameInput = document.createElement('input');
+  nameInput.type = 'text';
+  nameInput.className = 'settings-remote-name';
+  nameInput.placeholder = 'Device name';
+  nameInput.value = name || '';
+  var removeBtn = document.createElement('button');
+  removeBtn.className = 'settings-remote-remove';
+  removeBtn.textContent = '\u00d7';
+  removeBtn.setAttribute('aria-label', 'Remove remote instance');
+  row.appendChild(urlInput);
+  row.appendChild(nameInput);
+  row.appendChild(removeBtn);
+  return row;
+}
+
+/**
+ * Read remote instance rows from the DOM and save to server settings.
+ * Rebuilds _sources after saving so polling updates immediately.
+ */
+function _saveRemoteInstances() {
+  var container = $('setting-remote-instances');
+  if (!container) return;
+  var instances = [];
+  container.querySelectorAll('.settings-remote-row').forEach(function(row) {
+    var urlEl = row.querySelector('.settings-remote-url');
+    var nameEl = row.querySelector('.settings-remote-name');
+    var url = (urlEl && urlEl.value) ? urlEl.value.trim() : '';
+    var name = (nameEl && nameEl.value) ? nameEl.value.trim() : '';
+    if (url) {
+      instances.push({ url: url, name: name });
+    }
+  });
+  patchServerSetting('remote_instances', instances).then(function() {
+    _sources = buildSources(_serverSettings);
+  });
+}
+
 // ─── Settings dialog ──────────────────────────────────────────────────────────
 
 /**
@@ -1403,6 +1454,22 @@ function openSettings() {
       autoOpenEl.checked = ss && ss.auto_open !== undefined ? !!ss.auto_open : true;
     }
 
+    // Device name
+    const deviceNameEl = $('setting-device-name');
+    if (deviceNameEl) {
+      deviceNameEl.value = (ss && ss.device_name) || '';
+    }
+
+    // Remote instances
+    const remoteInstancesEl = $('setting-remote-instances');
+    if (remoteInstancesEl) {
+      remoteInstancesEl.innerHTML = '';
+      var remotes = (ss && ss.remote_instances) || [];
+      remotes.forEach(function(r) {
+        remoteInstancesEl.appendChild(_buildRemoteInstanceRow(r.url || '', r.name || ''));
+      });
+    }
+
     // New Session tab - populate template textarea
     const templateEl = $('setting-template');
     if (templateEl) {
@@ -1882,6 +1949,51 @@ function bindStaticEventListeners() {
     patchServerSetting('new_session_template', NEW_SESSION_DEFAULT_TEMPLATE);
   });
 
+  // Sessions tab — device name with 500ms debounce
+  var _deviceNameDebounceTimer;
+  on($('setting-device-name'), 'input', function() {
+    clearTimeout(_deviceNameDebounceTimer);
+    var val = this.value;
+    _deviceNameDebounceTimer = setTimeout(function() {
+      patchServerSetting('device_name', val).then(function() {
+        _sources = buildSources(_serverSettings);
+      });
+    }, 500);
+  });
+
+  // Sessions tab — add remote instance button
+  on($('add-remote-instance-btn'), 'click', function() {
+    var container = $('setting-remote-instances');
+    if (container) {
+      container.appendChild(_buildRemoteInstanceRow('', ''));
+    }
+  });
+
+  // Sessions tab — delegated remove handler on remote instances container
+  var remoteInstancesContainer = $('setting-remote-instances');
+  if (remoteInstancesContainer) {
+    remoteInstancesContainer.addEventListener('click', function(e) {
+      var removeBtn = e.target.closest && e.target.closest('.settings-remote-remove');
+      if (!removeBtn) return;
+      var row = removeBtn.closest('.settings-remote-row');
+      if (row) {
+        row.remove();
+        _saveRemoteInstances();
+      }
+    });
+
+    // Delegated input save with debounce for remote instance URL/name fields
+    var _remoteDebounceTimer;
+    remoteInstancesContainer.addEventListener('input', function(e) {
+      var input = e.target.closest && e.target.closest('.settings-remote-url, .settings-remote-name');
+      if (!input) return;
+      clearTimeout(_remoteDebounceTimer);
+      _remoteDebounceTimer = setTimeout(function() {
+        _saveRemoteInstances();
+      }, 500);
+    });
+  }
+
   // Filter bar — delegated click handler (pills are re-rendered each poll)
   var filterBarEl = $('filter-bar');
   if (filterBarEl) {
diff --git a/muxplex/frontend/index.html b/muxplex/frontend/index.html
index 3099e9f..b4a3906 100644
--- a/muxplex/frontend/index.html
+++ b/muxplex/frontend/index.html
@@ -164,6 +164,15 @@
             <label class="settings-label" for="setting-auto-open">Auto-open created sessions</label>
             <input type="checkbox" id="setting-auto-open" class="settings-checkbox" checked />
           </div>
+          <div class="settings-field">
+            <label class="settings-label" for="setting-device-name">Device Name</label>
+            <input type="text" id="setting-device-name" class="settings-input" placeholder="This device" />
+          </div>
+          <div class="settings-field settings-field--column">
+            <label class="settings-label">Remote Instances</label>
+            <div id="setting-remote-instances" class="settings-remote-list"></div>
+            <button id="add-remote-instance-btn" class="settings-action-btn">+ Add Remote</button>
+          </div>
         </div>
         <div class="settings-panel hidden" data-tab="notifications">
           <div class="settings-field">
diff --git a/muxplex/frontend/style.css b/muxplex/frontend/style.css
index 265417e..8537afd 100644
--- a/muxplex/frontend/style.css
+++ b/muxplex/frontend/style.css
@@ -1451,3 +1451,86 @@ body {
     display: none;
   }
 }
+
+/* ============================================================
+   Remote Instances UI (task-15)
+   ============================================================ */
+
+.settings-input {
+  flex: 1;
+  background: var(--bg-secondary);
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  color: var(--text);
+  font-size: 13px;
+  padding: 5px 8px;
+  outline: none;
+  transition: border-color 0.15s;
+}
+
+.settings-input:focus {
+  border-color: var(--accent);
+}
+
+.settings-remote-list {
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+  width: 100%;
+}
+
+.settings-remote-row {
+  display: flex;
+  gap: 6px;
+  align-items: center;
+}
+
+.settings-remote-url {
+  flex: 2;
+  background: var(--bg-secondary);
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  color: var(--text);
+  font-size: 13px;
+  padding: 5px 8px;
+  outline: none;
+  transition: border-color 0.15s;
+}
+
+.settings-remote-url:focus {
+  border-color: var(--accent);
+}
+
+.settings-remote-name {
+  flex: 1;
+  background: var(--bg-secondary);
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  color: var(--text);
+  font-size: 13px;
+  padding: 5px 8px;
+  outline: none;
+  transition: border-color 0.15s;
+}
+
+.settings-remote-name:focus {
+  border-color: var(--accent);
+}
+
+.settings-remote-remove {
+  flex-shrink: 0;
+  background: transparent;
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  color: var(--text-muted);
+  cursor: pointer;
+  font-size: 16px;
+  line-height: 1;
+  padding: 4px 8px;
+  transition: color 0.15s, border-color 0.15s;
+}
+
+.settings-remote-remove:hover {
+  border-color: var(--accent);
+  color: var(--text);
+}
diff --git a/muxplex/tests/test_frontend_css.py b/muxplex/tests/test_frontend_css.py
index 3ff7ff8..9990b42 100644
--- a/muxplex/tests/test_frontend_css.py
+++ b/muxplex/tests/test_frontend_css.py
@@ -1681,3 +1681,20 @@ def test_css_sidebar_footer() -> None:
     css = read_css()
     for cls in (".sidebar-footer", ".sidebar-new-btn"):
         assert cls in css, f"Missing CSS selector '{cls}'"
+
+
+# ─── Remote Instances UI (task-15) ────────────────────────────────────────────
+
+
+def test_css_remote_instances_classes() -> None:
+    """CSS classes for remote instances management must exist in style.css."""
+    css = read_css()
+    for cls in (
+        ".settings-remote-list",
+        ".settings-remote-row",
+        ".settings-remote-url",
+        ".settings-remote-name",
+        ".settings-remote-remove",
+        ".settings-input",
+    ):
+        assert cls in css, f"Missing CSS selector '{cls}' — required for Remote Instances UI"
diff --git a/muxplex/tests/test_frontend_html.py b/muxplex/tests/test_frontend_html.py
index 007b045..b04e937 100644
--- a/muxplex/tests/test_frontend_html.py
+++ b/muxplex/tests/test_frontend_html.py
@@ -1062,3 +1062,50 @@ def test_html_settings_close_btn_exists() -> None:
     assert dialog.find(id="settings-close-btn") is not None, (
         "#settings-close-btn must be a descendant of #settings-dialog"
     )
+
+
+# ============================================================
+# Remote Instances UI (task-15-remote-instances)
+# ============================================================
+
+
+def test_html_sessions_tab_device_name_input() -> None:
+    """Sessions tab must contain a #setting-device-name text input for the device name."""
+    soup = _SOUP
+    el = soup.find(id="setting-device-name")
+    assert el is not None, "Missing element with id='setting-device-name'"
+    # Must be inside the sessions panel
+    sessions_panel = soup.find("div", attrs={"data-tab": "sessions"})
+    assert sessions_panel is not None, "Missing sessions panel (data-tab='sessions')"
+    assert sessions_panel.find(id="setting-device-name") is not None, (
+        "#setting-device-name must be inside the sessions settings panel"
+    )
+
+
+def test_html_sessions_tab_remote_instances_container() -> None:
+    """Sessions tab must contain a #setting-remote-instances container for remote instance rows."""
+    soup = _SOUP
+    el = soup.find(id="setting-remote-instances")
+    assert el is not None, "Missing element with id='setting-remote-instances'"
+    # Must be inside the sessions panel
+    sessions_panel = soup.find("div", attrs={"data-tab": "sessions"})
+    assert sessions_panel is not None, "Missing sessions panel (data-tab='sessions')"
+    assert sessions_panel.find(id="setting-remote-instances") is not None, (
+        "#setting-remote-instances must be inside the sessions settings panel"
+    )
+
+
+def test_html_sessions_tab_add_remote_instance_btn() -> None:
+    """Sessions tab must contain an #add-remote-instance-btn button to add remote instances."""
+    soup = _SOUP
+    el = soup.find(id="add-remote-instance-btn")
+    assert el is not None, "Missing element with id='add-remote-instance-btn'"
+    assert el.name == "button", (
+        f"#add-remote-instance-btn must be a <button>, got: {el.name}"
+    )
+    # Must be inside the sessions panel
+    sessions_panel = soup.find("div", attrs={"data-tab": "sessions"})
+    assert sessions_panel is not None, "Missing sessions panel (data-tab='sessions')"
+    assert sessions_panel.find(id="add-remote-instance-btn") is not None, (
+        "#add-remote-instance-btn must be inside the sessions settings panel"
+    )
diff --git a/muxplex/tests/test_frontend_js.py b/muxplex/tests/test_frontend_js.py
index 8a13cf3..3055ec3 100644
--- a/muxplex/tests/test_frontend_js.py
+++ b/muxplex/tests/test_frontend_js.py
@@ -2296,3 +2296,123 @@ def test_dom_content_loaded_calls_load_server_settings() -> None:
         "DOMContentLoaded handler must call loadServerSettings() "
         "after startPolling() in the restoreState().then() chain"
     )
+
+
+# ─── Remote Instances UI (task-15) ────────────────────────────────────────────
+
+
+def test_save_remote_instances_function_exists() -> None:
+    """_saveRemoteInstances function must exist in app.js."""
+    assert "_saveRemoteInstances" in _JS, (
+        "_saveRemoteInstances function must be defined in app.js"
+    )
+
+
+def test_save_remote_instances_calls_patch_server_setting() -> None:
+    """_saveRemoteInstances must call patchServerSetting('remote_instances', ...)."""
+    match = re.search(
+        r"function _saveRemoteInstances\s*\(\s*\)\s*\{(.*?)(?=\n(?:function|//|window\.)|\n})",
+        _JS,
+        re.DOTALL,
+    )
+    assert match, "_saveRemoteInstances function not found in app.js"
+    body = match.group(1)
+    assert "patchServerSetting" in body, (
+        "_saveRemoteInstances must call patchServerSetting"
+    )
+    assert "remote_instances" in body, (
+        "_saveRemoteInstances must pass 'remote_instances' to patchServerSetting"
+    )
+
+
+def test_save_remote_instances_rebuilds_sources() -> None:
+    """_saveRemoteInstances must rebuild _sources after saving."""
+    match = re.search(
+        r"function _saveRemoteInstances\s*\(\s*\)\s*\{(.*?)(?=\n(?:function|//|window\.)|\n})",
+        _JS,
+        re.DOTALL,
+    )
+    assert match, "_saveRemoteInstances function not found in app.js"
+    body = match.group(1)
+    assert "_sources" in body or "buildSources" in body, (
+        "_saveRemoteInstances must rebuild _sources after saving remote_instances"
+    )
+
+
+def test_open_settings_populates_device_name() -> None:
+    """openSettings must populate setting-device-name from server settings."""
+    match = re.search(
+        r"function openSettings\s*\(\s*\)\s*\{(.*?)(?=\n(?:function|//\s*─))",
+        _JS,
+        re.DOTALL,
+    )
+    assert match, "openSettings function not found in app.js"
+    body = match.group(1)
+    assert "setting-device-name" in body, (
+        "openSettings must populate #setting-device-name input from server settings"
+    )
+    assert "device_name" in body, (
+        "openSettings must reference device_name from server settings"
+    )
+
+
+def test_open_settings_renders_remote_instances() -> None:
+    """openSettings must render remote instances rows from server settings."""
+    match = re.search(
+        r"function openSettings\s*\(\s*\)\s*\{(.*?)(?=\n(?:function|//\s*─))",
+        _JS,
+        re.DOTALL,
+    )
+    assert match, "openSettings function not found in app.js"
+    body = match.group(1)
+    assert "setting-remote-instances" in body, (
+        "openSettings must populate #setting-remote-instances from server settings"
+    )
+    assert "remote_instances" in body, (
+        "openSettings must reference remote_instances when rendering the instances list"
+    )
+
+
+def test_bind_static_event_listeners_device_name_debounce() -> None:
+    """bindStaticEventListeners must bind debounced save for setting-device-name."""
+    match = re.search(
+        r"function bindStaticEventListeners\s*\(\s*\)\s*\{(.*?)(?=\n(?:function|//\s*─|window\.))",
+        _JS,
+        re.DOTALL,
+    )
+    assert match, "bindStaticEventListeners function not found in app.js"
+    body = match.group(1)
+    assert "setting-device-name" in body, (
+        "bindStaticEventListeners must bind an event listener for #setting-device-name"
+    )
+    assert "device_name" in body, (
+        "bindStaticEventListeners must save device_name via patchServerSetting"
+    )
+
+
+def test_bind_static_event_listeners_add_remote_instance_btn() -> None:
+    """bindStaticEventListeners must bind the add-remote-instance-btn click handler."""
+    match = re.search(
+        r"function bindStaticEventListeners\s*\(\s*\)\s*\{(.*?)(?=\n(?:function|//\s*─|window\.))",
+        _JS,
+        re.DOTALL,
+    )
+    assert match, "bindStaticEventListeners function not found in app.js"
+    body = match.group(1)
+    assert "add-remote-instance-btn" in body, (
+        "bindStaticEventListeners must bind click handler for #add-remote-instance-btn"
+    )
+
+
+def test_bind_static_event_listeners_remote_instance_remove() -> None:
+    """bindStaticEventListeners must bind delegated handler for remote instance remove buttons."""
+    match = re.search(
+        r"function bindStaticEventListeners\s*\(\s*\)\s*\{(.*?)(?=\n(?:function|//\s*─|window\.))",
+        _JS,
+        re.DOTALL,
+    )
+    assert match, "bindStaticEventListeners function not found in app.js"
+    body = match.group(1)
+    assert "settings-remote-remove" in body, (
+        "bindStaticEventListeners must handle delegated clicks on .settings-remote-remove buttons"
+    )