diff --git a/config/instance-config.js b/config/instance-config.js
index 4c7f4917..12eca0cc 100644
--- a/config/instance-config.js
+++ b/config/instance-config.js
@@ -76,6 +76,17 @@ export const WATCH_HISTORY_LEGACY_LIST_IDENTIFIERS = Object.freeze([
   "watch-history:v2:index",
 ]);
 
+/**
+ * Whether to enable the V2 encrypted watch-history service.
+ *
+ * The runtime flag that controls this feature defaults to `false` so that new
+ * deployments stick with the analytics-only view flow until operators opt in.
+ * To enable V2, set `window.__BITVID_RUNTIME_FLAGS__.FEATURE_WATCH_HISTORY_V2 = true`
+ * in a bootstrap script (or override the value before the app loads). When the
+ * flag stays off, BitVid still emits legacy view events and will honor
+ * existing watch-history reads per plan §12, but the sync UI will surface a
+ * disabled banner instead of querying relays.
+ */
 /**
  * Maximum number of watch-history entries to retain per user.
  *
diff --git a/js/app.js b/js/app.js
index 1b7e4ddb..54162d5b 100644
--- a/js/app.js
+++ b/js/app.js
@@ -7585,7 +7585,16 @@ class bitvidApp {
       (async () => {
         let viewResult;
         try {
-          viewResult = await watchHistoryService.publishView(thresholdPointer);
+          const watchHistoryEnabled =
+            watchHistoryService?.isEnabled?.() === true &&
+            typeof watchHistoryService.publishView === "function";
+          if (watchHistoryEnabled) {
+            viewResult = await watchHistoryService.publishView(thresholdPointer);
+          } else if (typeof nostrClient?.recordVideoView === "function") {
+            viewResult = await nostrClient.recordVideoView(thresholdPointer);
+          } else {
+            viewResult = { ok: false, error: "view-logging-unavailable" };
+          }
         } catch (error) {
           if (isDevMode) {
             console.warn(
diff --git a/js/constants.js b/js/constants.js
index 831d3e3d..c13c4ab2 100644
--- a/js/constants.js
+++ b/js/constants.js
@@ -1,6 +1,6 @@
 const DEFAULT_FLAGS = Object.freeze({
-  URL_FIRST_ENABLED: true,   // try URL before magnet in the player
-  ACCEPT_LEGACY_V1: true,    // accept v1 magnet-only notes
+  URL_FIRST_ENABLED: true, // try URL before magnet in the player
+  ACCEPT_LEGACY_V1: true, // accept v1 magnet-only notes
   VIEW_FILTER_INCLUDE_LEGACY_VIDEO: false,
   FEATURE_WATCH_HISTORY_V2: false,
   WSS_TRACKERS: Object.freeze([
@@ -195,6 +195,10 @@ export function setViewFilterIncludeLegacyVideo(next) {
   return VIEW_FILTER_INCLUDE_LEGACY_VIDEO;
 }
 
+export function getWatchHistoryV2Enabled() {
+  return FEATURE_WATCH_HISTORY_V2 === true;
+}
+
 export function setWssTrackers(next) {
   runtimeFlags.WSS_TRACKERS = next;
   return WSS_TRACKERS;
diff --git a/js/historyView.js b/js/historyView.js
index 20832cbe..46a3e5d6 100644
--- a/js/historyView.js
+++ b/js/historyView.js
@@ -12,6 +12,9 @@ import { WATCH_HISTORY_BATCH_RESOLVE } from "./config.js";
 export const WATCH_HISTORY_EMPTY_COPY =
   "Your watch history is empty. Watch some videos to populate this list.";
 
+export const WATCH_HISTORY_DISABLED_COPY =
+  "Encrypted watch history sync is disabled by this server. Local history stays on this device only.";
+
 const WATCH_HISTORY_METADATA_PREF_KEY =
   "bitvid:watch-history:metadata-preference";
 const WATCH_HISTORY_PRIVACY_DISMISSED_KEY =
@@ -716,6 +719,7 @@ export function createWatchHistoryRenderer(config = {}) {
     metadataLabelSelector = "#profileHistoryMetadataLabel",
     metadataDescriptionSelector = "#profileHistoryMetadataDescription",
     emptyCopy = WATCH_HISTORY_EMPTY_COPY,
+    disabledCopy = WATCH_HISTORY_DISABLED_COPY,
     batchSize = WATCH_HISTORY_BATCH_SIZE,
     remove = (payload) => {
       const app = getAppInstance();
@@ -750,6 +754,7 @@ export function createWatchHistoryRenderer(config = {}) {
         ? watchHistoryService.shouldStoreMetadata() !== false
         : true,
     sessionFallbackActive: false,
+    featureEnabled: watchHistoryService.isEnabled?.() === true,
   };
 
   let elements = {
@@ -881,10 +886,12 @@ export function createWatchHistoryRenderer(config = {}) {
   }
 
   function updateFeatureBanner() {
+    const enabled = watchHistoryService.isEnabled?.() === true;
+    state.featureEnabled = enabled;
     if (!(elements.featureBanner instanceof HTMLElement)) {
       return;
     }
-    if (watchHistoryService.isEnabled?.() === true) {
+    if (enabled) {
       elements.featureBanner.textContent = "";
       setHidden(elements.featureBanner, true);
       return;
@@ -1018,6 +1025,31 @@ export function createWatchHistoryRenderer(config = {}) {
     }
   }
 
+  function showFeatureDisabledState() {
+    hideErrorBanner();
+    if (elements.loading) {
+      setHidden(elements.loading, true);
+    }
+    if (elements.status) {
+      setHidden(elements.status, true);
+    }
+    detachObserver();
+    if (elements.grid) {
+      elements.grid.innerHTML = "";
+      setHidden(elements.grid, true);
+    }
+    if (elements.empty) {
+      setTextContent(elements.empty, disabledCopy || emptyCopy);
+      setHidden(elements.empty, false);
+    }
+    if (elements.loadMore) {
+      setHidden(elements.loadMore, true);
+    }
+    if (elements.sentinel) {
+      setHidden(elements.sentinel, true);
+    }
+  }
+
   function ensureObserver() {
     if (!elements.sentinel || !WATCH_HISTORY_BATCH_RESOLVE) {
       return;
@@ -1553,6 +1585,17 @@ export function createWatchHistoryRenderer(config = {}) {
     if (state.isLoading) {
       return false;
     }
+    if (!state.featureEnabled) {
+      state.actor = null;
+      updateSessionFallbackWarning();
+      state.items = [];
+      state.fingerprint = "";
+      state.cursor = 0;
+      state.hasMore = false;
+      state.lastError = null;
+      showFeatureDisabledState();
+      return false;
+    }
     setLoadingState(true);
     const actor =
       typeof actorOverride === "string" && actorOverride.trim()
@@ -1642,6 +1685,15 @@ export function createWatchHistoryRenderer(config = {}) {
       ) === "true";
       updatePrivacyBanner();
       state.initialized = true;
+      if (!state.featureEnabled) {
+        state.items = [];
+        state.fingerprint = "";
+        state.cursor = 0;
+        state.hasMore = false;
+        state.lastError = null;
+        showFeatureDisabledState();
+        return;
+      }
       await this.refresh({ ...options, force: true });
     },
     async ensureInitialLoad(options = {}) {
@@ -1651,6 +1703,15 @@ export function createWatchHistoryRenderer(config = {}) {
       }
       refreshElements();
       updateFeatureBanner();
+      if (!state.featureEnabled) {
+        state.items = [];
+        state.fingerprint = "";
+        state.cursor = 0;
+        state.hasMore = false;
+        state.lastError = null;
+        showFeatureDisabledState();
+        return;
+      }
       bindMetadataToggle();
       state.metadataStorageEnabled =
         typeof watchHistoryService.shouldStoreMetadata === "function"
@@ -1659,6 +1720,16 @@ export function createWatchHistoryRenderer(config = {}) {
       updateMetadataToggle();
     },
     async refresh(options = {}) {
+      updateFeatureBanner();
+      if (!state.featureEnabled) {
+        state.items = [];
+        state.fingerprint = "";
+        state.cursor = 0;
+        state.hasMore = false;
+        state.lastError = null;
+        showFeatureDisabledState();
+        return;
+      }
       const { actor, force = true } = options;
       const changed = await loadHistory({
         force,
@@ -1671,6 +1742,9 @@ export function createWatchHistoryRenderer(config = {}) {
       await renderInitial();
     },
     async loadMore() {
+      if (!state.featureEnabled) {
+        return [];
+      }
       if (!state.items.length) {
         return [];
       }
diff --git a/js/watchHistoryService.js b/js/watchHistoryService.js
index 8990b5d6..cbbcdcba 100644
--- a/js/watchHistoryService.js
+++ b/js/watchHistoryService.js
@@ -10,7 +10,10 @@ import {
   WATCH_HISTORY_CACHE_TTL_MS,
   WATCH_HISTORY_MAX_ITEMS,
 } from "./config.js";
-import { FEATURE_WATCH_HISTORY_V2 } from "./constants.js";
+import {
+  FEATURE_WATCH_HISTORY_V2,
+  getWatchHistoryV2Enabled,
+} from "./constants.js";
 import { isDevMode } from "./config.js";
 
 const SESSION_STORAGE_KEY = "bitvid:watch-history:session:v1";
@@ -34,6 +37,18 @@ const state = {
 };
 
 function isFeatureEnabled() {
+  try {
+    if (typeof getWatchHistoryV2Enabled === "function") {
+      return getWatchHistoryV2Enabled();
+    }
+  } catch (error) {
+    if (isDevMode) {
+      console.warn(
+        "[watchHistoryService] Failed to read FEATURE_WATCH_HISTORY_V2 flag:",
+        error,
+      );
+    }
+  }
   return FEATURE_WATCH_HISTORY_V2 === true;
 }
 
@@ -439,6 +454,9 @@ function getOrCreateQueue(actorKey) {
 }
 
 function restoreQueueState() {
+  if (!isFeatureEnabled()) {
+    return;
+  }
   if (state.restored) {
     return;
   }
@@ -549,6 +567,9 @@ function restoreQueueState() {
 }
 
 function ensureQueue(actorKey) {
+  if (!isFeatureEnabled()) {
+    return null;
+  }
   if (!actorKey) {
     return null;
   }
@@ -559,6 +580,9 @@ function ensureQueue(actorKey) {
 }
 
 function persistQueueState() {
+  if (!isFeatureEnabled()) {
+    return;
+  }
   const storage = getSessionStorage();
   if (!storage) {
     return;
@@ -623,6 +647,9 @@ function resolveActorKey(actorInput) {
 }
 
 function collectQueueItems(actorKey) {
+  if (!isFeatureEnabled()) {
+    return [];
+  }
   const queue = state.queues.get(actorKey);
   if (!queue) {
     return [];
@@ -648,6 +675,9 @@ function collectQueueItems(actorKey) {
 }
 
 function notifyQueueChange(actorKey) {
+  if (!isFeatureEnabled()) {
+    return;
+  }
   emit("queue-changed", {
     actor: actorKey,
     items: collectQueueItems(actorKey),
@@ -655,6 +685,9 @@ function notifyQueueChange(actorKey) {
 }
 
 function clearQueue(actorKey) {
+  if (!isFeatureEnabled()) {
+    return;
+  }
   const queue = state.queues.get(actorKey);
   if (!queue) {
     return;
@@ -687,6 +720,9 @@ function resolveWatchedAt(...candidates) {
 }
 
 function scheduleRepublishForQueue(actorKey) {
+  if (!isFeatureEnabled()) {
+    return;
+  }
   const queue = state.queues.get(actorKey);
   if (!queue || !queue.pendingSnapshotId || queue.republishScheduled) {
     return;
@@ -1045,6 +1081,9 @@ async function getFingerprint(actorInput) {
 }
 
 function resetProgress(actorInput) {
+  if (!isFeatureEnabled()) {
+    return;
+  }
   const actorKey = normalizeActorKey(actorInput);
   if (actorKey) {
     state.queues.delete(actorKey);
@@ -1062,6 +1101,9 @@ function resetProgress(actorInput) {
 }
 
 function getQueuedPointers(actorInput) {
+  if (!isFeatureEnabled()) {
+    return [];
+  }
   const actorKey = normalizeActorKey(actorInput);
   if (!actorKey) {
     return [];
@@ -1073,6 +1115,9 @@ function getQueuedPointers(actorInput) {
 }
 
 function getAllQueues() {
+  if (!isFeatureEnabled()) {
+    return {};
+  }
   if (!state.restored) {
     restoreQueueState();
   }