diff --git a/realtime/src/server.ts b/realtime/src/server.ts
index 841faee..3a4ecaa 100644
--- a/realtime/src/server.ts
+++ b/realtime/src/server.ts
@@ -94,6 +94,10 @@ export const wss = new WebSocketServer({
 const ipConnections = new Map<string, number>();
 const ipConnectionTimestamps = new Map<string, number[]>();
 const unauthorizedAccessCooldown = new Map<string, UnauthorizedCooldownState>();
+const unauthorizedCooldownExpirations: UnauthorizedCooldownExpiryEntry[] = [];
+const MAX_UNAUTHORIZED_COOLDOWN_EXPIRATIONS_PER_CLEANUP = 512;
+const UNAUTHORIZED_COOLDOWN_HEAP_REBUILD_MIN_SIZE = 1024;
+const UNAUTHORIZED_COOLDOWN_HEAP_REBUILD_RATIO = 4;
 const ROOM_ID_PATTERN = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i;
 
 interface UnauthorizedCooldownState {
@@ -102,6 +106,11 @@ interface UnauthorizedCooldownState {
   suppressedAttempts: number;
 }
 
+interface UnauthorizedCooldownExpiryEntry {
+  key: string;
+  denyUntil: number;
+}
+
 interface AccessCheckData {
   allowed: boolean;
   accessLevel: RealtimeAccessLevel | null;
@@ -155,6 +164,122 @@ function buildUnauthorizedCooldownKey(roomId: string, clientIp: string, token: s
   return `${roomId}:${clientIp}:${getTokenFingerprint(token)}`;
 }
 
+function swapUnauthorizedCooldownHeapEntries(a: number, b: number): void {
+  const tmp = unauthorizedCooldownExpirations[a];
+  unauthorizedCooldownExpirations[a] = unauthorizedCooldownExpirations[b];
+  unauthorizedCooldownExpirations[b] = tmp;
+}
+
+function siftUnauthorizedCooldownExpirationUp(index: number): void {
+  let current = index;
+
+  while (current > 0) {
+    const parent = Math.floor((current - 1) / 2);
+    if (
+      unauthorizedCooldownExpirations[parent].denyUntil <=
+      unauthorizedCooldownExpirations[current].denyUntil
+    ) {
+      break;
+    }
+
+    swapUnauthorizedCooldownHeapEntries(parent, current);
+    current = parent;
+  }
+}
+
+function siftUnauthorizedCooldownExpirationDown(index: number): void {
+  let current = index;
+  const size = unauthorizedCooldownExpirations.length;
+
+  while (true) {
+    const left = current * 2 + 1;
+    const right = left + 1;
+    let smallest = current;
+
+    if (
+      left < size &&
+      unauthorizedCooldownExpirations[left].denyUntil <
+        unauthorizedCooldownExpirations[smallest].denyUntil
+    ) {
+      smallest = left;
+    }
+
+    if (
+      right < size &&
+      unauthorizedCooldownExpirations[right].denyUntil <
+        unauthorizedCooldownExpirations[smallest].denyUntil
+    ) {
+      smallest = right;
+    }
+
+    if (smallest === current) {
+      break;
+    }
+
+    swapUnauthorizedCooldownHeapEntries(current, smallest);
+    current = smallest;
+  }
+}
+
+function pushUnauthorizedCooldownExpiration(entry: UnauthorizedCooldownExpiryEntry): void {
+  unauthorizedCooldownExpirations.push(entry);
+  siftUnauthorizedCooldownExpirationUp(unauthorizedCooldownExpirations.length - 1);
+}
+
+function peekUnauthorizedCooldownExpiration(): UnauthorizedCooldownExpiryEntry | null {
+  return unauthorizedCooldownExpirations[0] ?? null;
+}
+
+function popUnauthorizedCooldownExpiration(): UnauthorizedCooldownExpiryEntry | null {
+  if (unauthorizedCooldownExpirations.length === 0) {
+    return null;
+  }
+
+  const root = unauthorizedCooldownExpirations[0];
+  const last = unauthorizedCooldownExpirations.pop();
+  if (unauthorizedCooldownExpirations.length > 0 && last) {
+    unauthorizedCooldownExpirations[0] = last;
+    siftUnauthorizedCooldownExpirationDown(0);
+  }
+
+  return root;
+}
+
+function rebuildUnauthorizedCooldownExpirationHeap(): void {
+  unauthorizedCooldownExpirations.length = 0;
+
+  for (const [key, state] of unauthorizedAccessCooldown.entries()) {
+    unauthorizedCooldownExpirations.push({
+      key,
+      denyUntil: state.denyUntil,
+    });
+  }
+
+  for (let i = Math.floor(unauthorizedCooldownExpirations.length / 2) - 1; i >= 0; i -= 1) {
+    siftUnauthorizedCooldownExpirationDown(i);
+  }
+}
+
+function maybeRebuildUnauthorizedCooldownExpirationHeap(): void {
+  if (unauthorizedCooldownExpirations.length < UNAUTHORIZED_COOLDOWN_HEAP_REBUILD_MIN_SIZE) {
+    return;
+  }
+
+  if (unauthorizedAccessCooldown.size === 0) {
+    unauthorizedCooldownExpirations.length = 0;
+    return;
+  }
+
+  if (
+    unauthorizedCooldownExpirations.length <=
+    unauthorizedAccessCooldown.size * UNAUTHORIZED_COOLDOWN_HEAP_REBUILD_RATIO
+  ) {
+    return;
+  }
+
+  rebuildUnauthorizedCooldownExpirationHeap();
+}
+
 function getUnauthorizedCooldownState(key: string, now: number): UnauthorizedCooldownState | null {
   const existingState = unauthorizedAccessCooldown.get(key);
   if (!existingState) {
@@ -173,6 +298,7 @@ function trackUnauthorizedAccess(key: string, now: number): UnauthorizedCooldown
   const existingState = getUnauthorizedCooldownState(key, now);
   if (existingState) {
     existingState.denyUntil = now + config.unauthorizedAccessCooldownMs;
+    pushUnauthorizedCooldownExpiration({ key, denyUntil: existingState.denyUntil });
     return existingState;
   }
 
@@ -183,6 +309,7 @@ function trackUnauthorizedAccess(key: string, now: number): UnauthorizedCooldown
   };
 
   unauthorizedAccessCooldown.set(key, nextState);
+  pushUnauthorizedCooldownExpiration({ key, denyUntil: nextState.denyUntil });
   return nextState;
 }
 
@@ -222,11 +349,40 @@ function logUnauthorizedRejection(
 }
 
 function cleanupExpiredUnauthorizedCooldown(now = Date.now()): void {
-  for (const [key, state] of unauthorizedAccessCooldown.entries()) {
-    if (state.denyUntil <= now) {
-      unauthorizedAccessCooldown.delete(key);
+  let processedEntries = 0;
+
+  while (processedEntries < MAX_UNAUTHORIZED_COOLDOWN_EXPIRATIONS_PER_CLEANUP) {
+    const nextExpiration = peekUnauthorizedCooldownExpiration();
+    if (!nextExpiration || nextExpiration.denyUntil > now) {
+      break;
+    }
+
+    const expiredEntry = popUnauthorizedCooldownExpiration();
+    if (!expiredEntry) {
+      break;
+    }
+
+    processedEntries += 1;
+
+    const existingState = unauthorizedAccessCooldown.get(expiredEntry.key);
+    if (!existingState) {
+      continue;
+    }
+
+    // The key may have been renewed after this heap entry was pushed.
+    if (existingState.denyUntil !== expiredEntry.denyUntil) {
+      continue;
     }
+
+    unauthorizedAccessCooldown.delete(expiredEntry.key);
   }
+
+  if (unauthorizedAccessCooldown.size === 0) {
+    unauthorizedCooldownExpirations.length = 0;
+    return;
+  }
+
+  maybeRebuildUnauthorizedCooldownExpirationHeap();
 }
 
 async function fetchAccess(token: string, roomId: string): Promise<AccessCheckData | null> {
diff --git a/realtime/tests/unit/server.test.ts b/realtime/tests/unit/server.test.ts
index eb3975f..3ab2b0c 100644
--- a/realtime/tests/unit/server.test.ts
+++ b/realtime/tests/unit/server.test.ts
@@ -70,6 +70,7 @@ const waitForConnectionProcessing = async () => {
 describe('Server', () => {
   let server: any;
   let wss: any;
+  let cleanupInactiveRooms: any;
   let setupWSConnectionMock: any;
   let memoryUsageSpy: any;
   let fetchMock: jest.MockedFunction<typeof fetch>;
@@ -103,6 +104,7 @@ describe('Server', () => {
     const serverModule = await import('../../src/server');
     server = serverModule.server;
     wss = serverModule.wss;
+    cleanupInactiveRooms = serverModule.cleanupInactiveRooms;
 
     const yjsUtilsModule = await import('../../src/yjs-utils');
     setupWSConnectionMock = yjsUtilsModule.setupWSConnection;
@@ -263,6 +265,59 @@ describe('Server', () => {
       }
     });
 
+    it('should not clear renewed cooldown state when stale expirations are cleaned', async () => {
+      jest.useFakeTimers();
+
+      try {
+        fetchMock.mockResolvedValue({
+          ok: true,
+          json: async () => ({
+            success: true,
+            data: {
+              allowed: false,
+              accessLevel: null,
+              owner: false,
+            },
+            error: null,
+          }),
+        } as Response);
+
+        const firstConn: any = new EventEmitter();
+        firstConn.close = jest.fn();
+        firstConn.readyState = WebSocket.OPEN;
+        wss.emit('connection', firstConn, mockReq);
+        await waitForConnectionProcessing();
+
+        expect(firstConn.close).toHaveBeenCalledWith(1008, 'Access denied');
+        expect(fetchMock).toHaveBeenCalledTimes(1);
+
+        await jest.advanceTimersByTimeAsync(15001);
+
+        const secondConn: any = new EventEmitter();
+        secondConn.close = jest.fn();
+        secondConn.readyState = WebSocket.OPEN;
+        wss.emit('connection', secondConn, mockReq);
+        await waitForConnectionProcessing();
+
+        expect(secondConn.close).toHaveBeenCalledWith(1008, 'Access denied');
+        expect(fetchMock).toHaveBeenCalledTimes(2);
+
+        cleanupInactiveRooms();
+
+        const thirdConn: any = new EventEmitter();
+        thirdConn.close = jest.fn();
+        thirdConn.readyState = WebSocket.OPEN;
+        wss.emit('connection', thirdConn, mockReq);
+        await waitForConnectionProcessing();
+
+        // Third attempt is still blocked by the renewed cooldown, so no new access check runs.
+        expect(thirdConn.close).toHaveBeenCalledWith(1008, 'Access denied');
+        expect(fetchMock).toHaveBeenCalledTimes(2);
+      } finally {
+        jest.useRealTimers();
+      }
+    });
+
     it('should handle synchronous error in setupWSConnection', async () => {
       // Mock setupWSConnection to throw synchronously
       setupWSConnectionMock.mockImplementationOnce(() => {
diff --git a/web/services/indexed-db.service.ts b/web/services/indexed-db.service.ts
index fd23d5f..36f1e1f 100644
--- a/web/services/indexed-db.service.ts
+++ b/web/services/indexed-db.service.ts
@@ -7,7 +7,7 @@ const DOCUMENTS_STORE = 'documents';
 class IndexedDBService {
   private static instance: IndexedDBService;
   private dbPromise: Promise<IDBPDatabase> | null = null;
-  private dbClosingPromise: Promise<void> | null = null;
+  private dbSwitchPromise: Promise<void> = Promise.resolve();
   private isSupported: boolean = true;
   private currentUserId: string | null = null;
 
@@ -35,22 +35,42 @@ class IndexedDBService {
 
     this.currentUserId = userId;
 
-    if (this.dbPromise && !this.dbClosingPromise) {
-      const dbPromiseToClose = this.dbPromise;
+    this.dbSwitchPromise = this.dbSwitchPromise
+      .then(async () => {
+        await this.closeCurrentConnection();
+      })
+      .catch((error) => {
+        console.warn('Failed to process IndexedDB user switch:', error);
+      });
+  }
+
+  private async awaitStableUserSwitch(): Promise<void> {
+    while (true) {
+      const inFlightSwitch = this.dbSwitchPromise;
+      await inFlightSwitch;
 
-      this.dbClosingPromise = dbPromiseToClose
-        .then((db) => {
-          db.close();
-        })
-        .catch((error) => {
-          console.warn('Failed to close IndexedDB connection during user switch:', error);
-        })
-        .finally(() => {
-          if (this.dbPromise === dbPromiseToClose) {
-            this.dbPromise = null;
-          }
-          this.dbClosingPromise = null;
-        });
+      // A newer switch may have been queued while awaiting this one.
+      if (inFlightSwitch === this.dbSwitchPromise) {
+        return;
+      }
+    }
+  }
+
+  private async closeCurrentConnection(): Promise<void> {
+    const dbPromiseToClose = this.dbPromise;
+    if (!dbPromiseToClose) {
+      return;
+    }
+
+    try {
+      const db = await dbPromiseToClose;
+      db.close();
+    } catch (error) {
+      console.warn('Failed to close IndexedDB connection during user switch:', error);
+    } finally {
+      if (this.dbPromise === dbPromiseToClose) {
+        this.dbPromise = null;
+      }
     }
   }
 
@@ -59,9 +79,7 @@ class IndexedDBService {
       throw new Error('IndexedDB not supported');
     }
 
-    if (this.dbClosingPromise) {
-      await this.dbClosingPromise;
-    }
+    await this.awaitStableUserSwitch();
 
     if (!this.dbPromise) {
       this.dbPromise = this.initDB();
@@ -208,11 +226,8 @@ class IndexedDBService {
 
   public async wipeDatabase(): Promise<void> {
     try {
-      if (this.dbPromise) {
-        const db = await this.dbPromise;
-        db.close();
-        this.dbPromise = null;
-      }
+      await this.awaitStableUserSwitch();
+      await this.closeCurrentConnection();
       await deleteDB(this.dbName);
     } catch (error) {
       console.error('Failed to wipe database:', error);
diff --git a/web/tests/unit/services/indexed-db.service.test.ts b/web/tests/unit/services/indexed-db.service.test.ts
index 24a87e1..839e743 100644
--- a/web/tests/unit/services/indexed-db.service.test.ts
+++ b/web/tests/unit/services/indexed-db.service.test.ts
@@ -226,6 +226,34 @@ describe('indexed-db.service', () => {
       expect(await indexedDBService.getDocument('doc-A')).toBeDefined();
       expect(await indexedDBService.getDocument('doc-B')).toBeUndefined();
     });
+
+    it('should honor the latest user context after rapid user switches', async () => {
+      indexedDBService.setUserId('rapid-user-A');
+      await indexedDBService.saveDocument({
+        id: 'doc-rapid-A',
+        meta: { title: 'A', createdAt: '', updatedAt: '' },
+        yjsState: new Uint8Array([1]),
+        version: 1,
+      });
+
+      indexedDBService.setUserId('rapid-user-B');
+      indexedDBService.setUserId('rapid-user-C');
+      indexedDBService.setUserId('rapid-user-B');
+
+      await indexedDBService.saveDocument({
+        id: 'doc-rapid-B',
+        meta: { title: 'B', createdAt: '', updatedAt: '' },
+        yjsState: new Uint8Array([2]),
+        version: 1,
+      });
+
+      expect(indexedDBService.dbName).toBe('nextdocs-db_rapid-user-B');
+      expect(await indexedDBService.getDocument('doc-rapid-B')).toBeDefined();
+
+      indexedDBService.setUserId('rapid-user-A');
+      expect(await indexedDBService.getDocument('doc-rapid-B')).toBeUndefined();
+      expect(await indexedDBService.getDocument('doc-rapid-A')).toBeDefined();
+    });
   });
 
   describe('isAvailable', () => {