diff --git a/src/app/op-log/backup/state-snapshot.service.spec.ts b/src/app/op-log/backup/state-snapshot.service.spec.ts
new file mode 100644
index 000000000..e1417d036
--- /dev/null
+++ b/src/app/op-log/backup/state-snapshot.service.spec.ts
@@ -0,0 +1,248 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
+import { TestBed } from '@angular/core/testing';
+import { provideMockStore, MockStore } from '@ngrx/store/testing';
+import { StateSnapshotService } from './state-snapshot.service';
+import { ArchiveDbAdapter } from '../../core/persistence/archive-db-adapter.service';
+import { selectTaskFeatureState } from '../../features/tasks/store/task.selectors';
+import { selectProjectFeatureState } from '../../features/project/store/project.selectors';
+import { selectTagFeatureState } from '../../features/tag/store/tag.reducer';
+import { selectConfigFeatureState } from '../../features/config/store/global-config.reducer';
+import { selectNoteFeatureState } from '../../features/note/store/note.reducer';
+import { selectIssueProviderState } from '../../features/issue/store/issue-provider.selectors';
+import { selectPlannerState } from '../../features/planner/store/planner.selectors';
+import { selectBoardsState } from '../../features/boards/store/boards.selectors';
+import { selectMetricFeatureState } from '../../features/metric/store/metric.selectors';
+import { selectSimpleCounterFeatureState } from '../../features/simple-counter/store/simple-counter.reducer';
+import { selectTaskRepeatCfgFeatureState } from '../../features/task-repeat-cfg/store/task-repeat-cfg.selectors';
+import { selectMenuTreeState } from '../../features/menu-tree/store/menu-tree.selectors';
+import { selectTimeTrackingState } from '../../features/time-tracking/store/time-tracking.selectors';
+import { selectPluginUserDataFeatureState } from '../../plugins/store/plugin-user-data.reducer';
+import { selectPluginMetadataFeatureState } from '../../plugins/store/plugin-metadata.reducer';
+import { selectReminderFeatureState } from '../../features/reminder/store/reminder.reducer';
+import { ArchiveModel } from '../../features/time-tracking/time-tracking.model';
+import { initialTimeTrackingState } from '../../features/time-tracking/store/time-tracking.reducer';
+
+describe('StateSnapshotService', () => {
+  let service: StateSnapshotService;
+  let store: MockStore;
+  let archiveDbAdapterSpy: jasmine.SpyObj<ArchiveDbAdapter>;
+
+  // Sample mock states for selectors
+  const mockTaskState = {
+    ids: ['task1'],
+    entities: { task1: { id: 'task1', title: 'Test Task' } },
+    selectedTaskId: 'task1',
+    currentTaskId: 'task1',
+  };
+  const mockProjectState = { ids: [], entities: {} };
+  const mockTagState = { ids: [], entities: {} };
+  const mockConfigState = { misc: {} };
+  const mockNoteState = { ids: [], entities: {} };
+  const mockIssueProviderState = { ids: [], entities: {} };
+  const mockPlannerState = { days: {} };
+  const mockBoardsState = { ids: [], entities: {} };
+  const mockMetricState = { ids: [], entities: {} };
+  const mockSimpleCounterState = { ids: [], entities: {} };
+  const mockTaskRepeatCfgState = { ids: [], entities: {} };
+  const mockMenuTreeState = { root: [] };
+  const mockTimeTrackingState = initialTimeTrackingState;
+  const mockPluginUserDataState = {};
+  const mockPluginMetadataState = {};
+  const mockReminderState = { ids: [], entities: {} };
+
+  const DEFAULT_ARCHIVE: ArchiveModel = {
+    task: { ids: [], entities: {} },
+    timeTracking: initialTimeTrackingState,
+    lastTimeTrackingFlush: 0,
+  };
+
+  const mockArchiveYoung: ArchiveModel = {
+    task: {
+      ids: ['archived1'],
+      entities: { archived1: { id: 'archived1', title: 'Archived Young' } as any },
+    },
+    timeTracking: initialTimeTrackingState,
+    lastTimeTrackingFlush: 1000,
+  };
+
+  const mockArchiveOld: ArchiveModel = {
+    task: {
+      ids: ['archivedOld1'],
+      entities: {
+        archivedOld1: { id: 'archivedOld1', title: 'Archived Old' } as any,
+      },
+    },
+    timeTracking: initialTimeTrackingState,
+    lastTimeTrackingFlush: 500,
+  };
+
+  beforeEach(() => {
+    archiveDbAdapterSpy = jasmine.createSpyObj('ArchiveDbAdapter', [
+      'loadArchiveYoung',
+      'loadArchiveOld',
+    ]);
+    archiveDbAdapterSpy.loadArchiveYoung.and.returnValue(
+      Promise.resolve(mockArchiveYoung),
+    );
+    archiveDbAdapterSpy.loadArchiveOld.and.returnValue(Promise.resolve(mockArchiveOld));
+
+    TestBed.configureTestingModule({
+      providers: [
+        StateSnapshotService,
+        provideMockStore(),
+        { provide: ArchiveDbAdapter, useValue: archiveDbAdapterSpy },
+      ],
+    });
+
+    service = TestBed.inject(StateSnapshotService);
+    store = TestBed.inject(MockStore);
+
+    // Override selectors with mock values
+    store.overrideSelector(selectTaskFeatureState, mockTaskState as any);
+    store.overrideSelector(selectProjectFeatureState, mockProjectState as any);
+    store.overrideSelector(selectTagFeatureState, mockTagState as any);
+    store.overrideSelector(selectConfigFeatureState, mockConfigState as any);
+    store.overrideSelector(selectNoteFeatureState, mockNoteState as any);
+    store.overrideSelector(selectIssueProviderState, mockIssueProviderState as any);
+    store.overrideSelector(selectPlannerState, mockPlannerState as any);
+    store.overrideSelector(selectBoardsState, mockBoardsState as any);
+    store.overrideSelector(selectMetricFeatureState, mockMetricState as any);
+    store.overrideSelector(
+      selectSimpleCounterFeatureState,
+      mockSimpleCounterState as any,
+    );
+    store.overrideSelector(
+      selectTaskRepeatCfgFeatureState,
+      mockTaskRepeatCfgState as any,
+    );
+    store.overrideSelector(selectMenuTreeState, mockMenuTreeState as any);
+    store.overrideSelector(selectTimeTrackingState, mockTimeTrackingState as any);
+    store.overrideSelector(
+      selectPluginUserDataFeatureState,
+      mockPluginUserDataState as any,
+    );
+    store.overrideSelector(
+      selectPluginMetadataFeatureState,
+      mockPluginMetadataState as any,
+    );
+    store.overrideSelector(selectReminderFeatureState, mockReminderState as any);
+  });
+
+  afterEach(() => {
+    store.resetSelectors();
+  });
+
+  describe('getStateSnapshot (sync)', () => {
+    it('should return all feature states from NgRx store', () => {
+      const snapshot = service.getStateSnapshot();
+
+      expect(snapshot.project).toEqual(mockProjectState);
+      expect(snapshot.tag).toEqual(mockTagState);
+      expect(snapshot.globalConfig).toEqual(mockConfigState);
+      expect(snapshot.note).toEqual(mockNoteState);
+      expect(snapshot.issueProvider).toEqual(mockIssueProviderState);
+      expect(snapshot.planner).toEqual(mockPlannerState);
+      expect(snapshot.boards).toEqual(mockBoardsState);
+      expect(snapshot.metric).toEqual(mockMetricState);
+      expect(snapshot.simpleCounter).toEqual(mockSimpleCounterState);
+      expect(snapshot.taskRepeatCfg).toEqual(mockTaskRepeatCfgState);
+      expect(snapshot.menuTree).toEqual(mockMenuTreeState);
+      expect(snapshot.timeTracking).toEqual(mockTimeTrackingState);
+      expect(snapshot.pluginUserData).toEqual(mockPluginUserDataState);
+      expect(snapshot.pluginMetadata).toEqual(mockPluginMetadataState);
+      expect(snapshot.reminders).toEqual(mockReminderState);
+    });
+
+    it('should return default empty archives', () => {
+      const snapshot = service.getStateSnapshot();
+
+      expect(snapshot.archiveYoung).toEqual(DEFAULT_ARCHIVE);
+      expect(snapshot.archiveOld).toEqual(DEFAULT_ARCHIVE);
+    });
+
+    it('should clear currentTaskId', () => {
+      const snapshot = service.getStateSnapshot();
+
+      expect((snapshot.task as any).currentTaskId).toBeNull();
+    });
+
+    it('should include task state with ids and entities', () => {
+      const snapshot = service.getStateSnapshot();
+
+      expect((snapshot.task as any).ids).toEqual(['task1']);
+      expect((snapshot.task as any).entities).toBeDefined();
+    });
+  });
+
+  describe('getStateSnapshotAsync', () => {
+    it('should return all feature states from NgRx store', async () => {
+      const snapshot = await service.getStateSnapshotAsync();
+
+      expect(snapshot.project).toEqual(mockProjectState);
+      expect(snapshot.tag).toEqual(mockTagState);
+      expect(snapshot.globalConfig).toEqual(mockConfigState);
+    });
+
+    it('should load archiveYoung from ArchiveDbAdapter', async () => {
+      const snapshot = await service.getStateSnapshotAsync();
+
+      expect(archiveDbAdapterSpy.loadArchiveYoung).toHaveBeenCalled();
+      expect(snapshot.archiveYoung).toEqual(mockArchiveYoung);
+    });
+
+    it('should load archiveOld from ArchiveDbAdapter', async () => {
+      const snapshot = await service.getStateSnapshotAsync();
+
+      expect(archiveDbAdapterSpy.loadArchiveOld).toHaveBeenCalled();
+      expect(snapshot.archiveOld).toEqual(mockArchiveOld);
+    });
+
+    it('should return default archive when adapter returns null for archiveYoung', async () => {
+      archiveDbAdapterSpy.loadArchiveYoung.and.returnValue(Promise.resolve(null as any));
+
+      const snapshot = await service.getStateSnapshotAsync();
+
+      expect(snapshot.archiveYoung).toEqual(DEFAULT_ARCHIVE);
+    });
+
+    it('should return default archive when adapter returns null for archiveOld', async () => {
+      archiveDbAdapterSpy.loadArchiveOld.and.returnValue(Promise.resolve(null as any));
+
+      const snapshot = await service.getStateSnapshotAsync();
+
+      expect(snapshot.archiveOld).toEqual(DEFAULT_ARCHIVE);
+    });
+
+    it('should clear currentTaskId in async version', async () => {
+      const snapshot = await service.getStateSnapshotAsync();
+
+      expect((snapshot.task as any).currentTaskId).toBeNull();
+    });
+
+    it('should load both archives in parallel', async () => {
+      // Both should be called
+      await service.getStateSnapshotAsync();
+
+      expect(archiveDbAdapterSpy.loadArchiveYoung).toHaveBeenCalledTimes(1);
+      expect(archiveDbAdapterSpy.loadArchiveOld).toHaveBeenCalledTimes(1);
+    });
+  });
+
+  describe('backward compatibility aliases', () => {
+    it('getAllSyncModelDataFromStore should call getStateSnapshot', () => {
+      spyOn(service, 'getStateSnapshot').and.callThrough();
+
+      service.getAllSyncModelDataFromStore();
+
+      expect(service.getStateSnapshot).toHaveBeenCalled();
+    });
+
+    it('getAllSyncModelDataFromStoreAsync should call getStateSnapshotAsync', async () => {
+      spyOn(service, 'getStateSnapshotAsync').and.callThrough();
+
+      await service.getAllSyncModelDataFromStoreAsync();
+
+      expect(service.getStateSnapshotAsync).toHaveBeenCalled();
+    });
+  });
+});
diff --git a/src/app/op-log/sync/lww-operation-factory.service.spec.ts b/src/app/op-log/sync/lww-operation-factory.service.spec.ts
new file mode 100644
index 000000000..d1dd69668
--- /dev/null
+++ b/src/app/op-log/sync/lww-operation-factory.service.spec.ts
@@ -0,0 +1,249 @@
+import { TestBed } from '@angular/core/testing';
+import { LWWOperationFactory } from './lww-operation-factory.service';
+import { EntityType, OpType, VectorClock } from '../core/operation.types';
+import { CURRENT_SCHEMA_VERSION } from '../persistence/schema-migration.service';
+
+describe('LWWOperationFactory', () => {
+  let service: LWWOperationFactory;
+
+  beforeEach(() => {
+    TestBed.configureTestingModule({
+      providers: [LWWOperationFactory],
+    });
+    service = TestBed.inject(LWWOperationFactory);
+  });
+
+  describe('createLWWUpdateOp', () => {
+    const entityType: EntityType = 'TASK';
+    const entityId = 'task-123';
+    const entityState = { id: entityId, title: 'Test Task', done: false };
+    const clientId = 'client_abc';
+    const vectorClock: VectorClock = { client_abc: 5, client_xyz: 3 };
+    const timestamp = 1700000000000;
+
+    it('should create operation with correct action type format [ENTITY] LWW Update', () => {
+      const op = service.createLWWUpdateOp(
+        entityType,
+        entityId,
+        entityState,
+        clientId,
+        vectorClock,
+        timestamp,
+      );
+
+      expect(op.actionType).toBe('[TASK] LWW Update');
+    });
+
+    it('should create action type for different entity types', () => {
+      const projectOp = service.createLWWUpdateOp(
+        'PROJECT',
+        'proj-1',
+        {},
+        clientId,
+        vectorClock,
+        timestamp,
+      );
+      expect(projectOp.actionType).toBe('[PROJECT] LWW Update');
+
+      const tagOp = service.createLWWUpdateOp(
+        'TAG',
+        'tag-1',
+        {},
+        clientId,
+        vectorClock,
+        timestamp,
+      );
+      expect(tagOp.actionType).toBe('[TAG] LWW Update');
+    });
+
+    it('should assign correct opType (Update)', () => {
+      const op = service.createLWWUpdateOp(
+        entityType,
+        entityId,
+        entityState,
+        clientId,
+        vectorClock,
+        timestamp,
+      );
+
+      expect(op.opType).toBe(OpType.Update);
+    });
+
+    it('should use provided entityType and entityId', () => {
+      const op = service.createLWWUpdateOp(
+        entityType,
+        entityId,
+        entityState,
+        clientId,
+        vectorClock,
+        timestamp,
+      );
+
+      expect(op.entityType).toBe(entityType);
+      expect(op.entityId).toBe(entityId);
+    });
+
+    it('should include entityState as payload', () => {
+      const op = service.createLWWUpdateOp(
+        entityType,
+        entityId,
+        entityState,
+        clientId,
+        vectorClock,
+        timestamp,
+      );
+
+      expect(op.payload).toEqual(entityState);
+    });
+
+    it('should generate UUIDv7 ID', () => {
+      const op = service.createLWWUpdateOp(
+        entityType,
+        entityId,
+        entityState,
+        clientId,
+        vectorClock,
+        timestamp,
+      );
+
+      // UUIDv7 format: 8-4-4-4-12 hex characters
+      expect(op.id).toMatch(
+        /^[0-9a-f]{8}-[0-9a-f]{4}-7[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i,
+      );
+    });
+
+    it('should generate unique IDs for each call', () => {
+      const op1 = service.createLWWUpdateOp(
+        entityType,
+        entityId,
+        entityState,
+        clientId,
+        vectorClock,
+        timestamp,
+      );
+      const op2 = service.createLWWUpdateOp(
+        entityType,
+        entityId,
+        entityState,
+        clientId,
+        vectorClock,
+        timestamp,
+      );
+
+      expect(op1.id).not.toBe(op2.id);
+    });
+
+    it('should include CURRENT_SCHEMA_VERSION', () => {
+      const op = service.createLWWUpdateOp(
+        entityType,
+        entityId,
+        entityState,
+        clientId,
+        vectorClock,
+        timestamp,
+      );
+
+      expect(op.schemaVersion).toBe(CURRENT_SCHEMA_VERSION);
+    });
+
+    it('should preserve provided vectorClock', () => {
+      const op = service.createLWWUpdateOp(
+        entityType,
+        entityId,
+        entityState,
+        clientId,
+        vectorClock,
+        timestamp,
+      );
+
+      expect(op.vectorClock).toEqual(vectorClock);
+    });
+
+    it('should preserve provided timestamp', () => {
+      const op = service.createLWWUpdateOp(
+        entityType,
+        entityId,
+        entityState,
+        clientId,
+        vectorClock,
+        timestamp,
+      );
+
+      expect(op.timestamp).toBe(timestamp);
+    });
+
+    it('should preserve provided clientId', () => {
+      const op = service.createLWWUpdateOp(
+        entityType,
+        entityId,
+        entityState,
+        clientId,
+        vectorClock,
+        timestamp,
+      );
+
+      expect(op.clientId).toBe(clientId);
+    });
+  });
+
+  describe('mergeAndIncrementClocks', () => {
+    it('should return incremented clock for single input clock', () => {
+      const clock: VectorClock = { clientA: 5 };
+      const result = service.mergeAndIncrementClocks([clock], 'clientA');
+
+      expect(result).toEqual({ clientA: 6 });
+    });
+
+    it('should merge two clocks taking max of each component', () => {
+      const clock1: VectorClock = { clientA: 5, clientB: 3 };
+      const clock2: VectorClock = { clientA: 3, clientB: 7 };
+      const result = service.mergeAndIncrementClocks([clock1, clock2], 'clientA');
+
+      expect(result['clientA']).toBe(6); // max(5,3) + 1
+      expect(result['clientB']).toBe(7); // max(3,7)
+    });
+
+    it('should merge three+ clocks correctly', () => {
+      const clock1: VectorClock = { clientA: 1 };
+      const clock2: VectorClock = { clientA: 5, clientB: 2 };
+      const clock3: VectorClock = { clientB: 8, clientC: 3 };
+      const result = service.mergeAndIncrementClocks([clock1, clock2, clock3], 'clientA');
+
+      expect(result['clientA']).toBe(6); // max(1,5,0) + 1
+      expect(result['clientB']).toBe(8); // max(0,2,8)
+      expect(result['clientC']).toBe(3); // max(0,0,3)
+    });
+
+    it('should handle empty clocks array', () => {
+      const result = service.mergeAndIncrementClocks([], 'clientA');
+
+      expect(result).toEqual({ clientA: 1 });
+    });
+
+    it('should increment merged clock for given clientId', () => {
+      const clock: VectorClock = { clientA: 10, clientB: 5 };
+      const result = service.mergeAndIncrementClocks([clock], 'clientB');
+
+      expect(result['clientA']).toBe(10); // unchanged
+      expect(result['clientB']).toBe(6); // incremented
+    });
+
+    it('should add new clientId if not in any input clocks', () => {
+      const clock: VectorClock = { clientA: 5 };
+      const result = service.mergeAndIncrementClocks([clock], 'clientNew');
+
+      expect(result['clientA']).toBe(5); // preserved
+      expect(result['clientNew']).toBe(1); // new entry, starts at 1
+    });
+
+    it('should handle clocks with non-overlapping clients', () => {
+      const clock1: VectorClock = { clientA: 3 };
+      const clock2: VectorClock = { clientB: 7 };
+      const result = service.mergeAndIncrementClocks([clock1, clock2], 'clientC');
+
+      expect(result['clientA']).toBe(3);
+      expect(result['clientB']).toBe(7);
+      expect(result['clientC']).toBe(1);
+    });
+  });
+});
diff --git a/src/app/op-log/sync/remote-ops-processing.service.spec.ts b/src/app/op-log/sync/remote-ops-processing.service.spec.ts
index 5dc61def7..60d09f63c 100644
--- a/src/app/op-log/sync/remote-ops-processing.service.spec.ts
+++ b/src/app/op-log/sync/remote-ops-processing.service.spec.ts
@@ -52,6 +52,7 @@ describe('RemoteOpsProcessingService', () => {
       'getUnsynced',
       'hasOp',
       'append',
+      'appendBatch',
       'appendWithVectorClockUpdate',
       'markApplied',
       'markFailed',
@@ -65,6 +66,10 @@ describe('RemoteOpsProcessingService', () => {
     ]);
     // By default, treat all ops as new (return them as-is)
     opLogStoreSpy.filterNewOps.and.callFake((ops: any[]) => Promise.resolve(ops));
+    // By default, appendBatch returns sequential seq numbers starting from 1
+    opLogStoreSpy.appendBatch.and.callFake((ops: any[]) =>
+      Promise.resolve(ops.map((_: any, i: number) => i + 1)),
+    );
     // By default, no full-state ops in store
     opLogStoreSpy.getLatestFullStateOp.and.returnValue(Promise.resolve(undefined));
     // By default, mergeRemoteOpClocks succeeds
@@ -309,13 +314,11 @@ describe('RemoteOpsProcessingService', () => {
       vectorClockServiceSpy.getEntityFrontier.and.returnValue(Promise.resolve(new Map()));
       vectorClockServiceSpy.getSnapshotVectorClock.and.returnValue(Promise.resolve({}));
       opLogStoreSpy.hasOp.and.returnValue(Promise.resolve(false));
-      opLogStoreSpy.append.and.returnValue(Promise.resolve(1));
 
       await service.processRemoteOps(remoteOps);
 
-      // Only op1 should be applied
-      expect(opLogStoreSpy.append).toHaveBeenCalledTimes(1);
-      expect(opLogStoreSpy.append).toHaveBeenCalledWith(remoteOps[0], 'remote', {
+      // Only op1 should be applied (appendBatch called with single-element array)
+      expect(opLogStoreSpy.appendBatch).toHaveBeenCalledWith([remoteOps[0]], 'remote', {
         pendingApply: true,
       });
     });
@@ -338,18 +341,15 @@ describe('RemoteOpsProcessingService', () => {
       vectorClockServiceSpy.getEntityFrontier.and.returnValue(Promise.resolve(new Map()));
       vectorClockServiceSpy.getSnapshotVectorClock.and.returnValue(Promise.resolve({}));
       opLogStoreSpy.hasOp.and.returnValue(Promise.resolve(false));
-      opLogStoreSpy.append.and.returnValue(Promise.resolve(1));
 
       await service.processRemoteOps(remoteOps);
 
-      // op1 and op3 should be processed, 'throws' is skipped
-      expect(opLogStoreSpy.append).toHaveBeenCalledTimes(2);
-      expect(opLogStoreSpy.append).toHaveBeenCalledWith(remoteOps[0], 'remote', {
-        pendingApply: true,
-      });
-      expect(opLogStoreSpy.append).toHaveBeenCalledWith(remoteOps[2], 'remote', {
-        pendingApply: true,
-      });
+      // op1 and op3 should be processed (appendBatch called with array of both)
+      expect(opLogStoreSpy.appendBatch).toHaveBeenCalledWith(
+        [remoteOps[0], remoteOps[2]],
+        'remote',
+        { pendingApply: true },
+      );
     });
 
     it('should return early when all ops fail migration', async () => {
@@ -395,8 +395,10 @@ describe('RemoteOpsProcessingService', () => {
       // (used for potential dependency warnings in future enhancements)
       await service.processRemoteOps(remoteOps);
 
-      // Only op1 should be applied
-      expect(opLogStoreSpy.append).toHaveBeenCalledTimes(1);
+      // Only op1 should be applied (appendBatch called with single-element array)
+      expect(opLogStoreSpy.appendBatch).toHaveBeenCalledWith([remoteOps[0]], 'remote', {
+        pendingApply: true,
+      });
     });
 
     it('should show error snackbar and abort if version is too new', async () => {
@@ -462,8 +464,10 @@ describe('RemoteOpsProcessingService', () => {
         }),
       );
 
-      // Should still process the ops (ops are applied)
-      expect(opLogStoreSpy.append).toHaveBeenCalledTimes(2);
+      // Should still process the ops (appendBatch called with both ops)
+      expect(opLogStoreSpy.appendBatch).toHaveBeenCalledWith(remoteOps, 'remote', {
+        pendingApply: true,
+      });
     });
 
     it('should not show newer version warning again in same session', async () => {
diff --git a/src/app/op-log/sync/remote-ops-processing.service.ts b/src/app/op-log/sync/remote-ops-processing.service.ts
index a752a2070..ab4329968 100644
--- a/src/app/op-log/sync/remote-ops-processing.service.ts
+++ b/src/app/op-log/sync/remote-ops-processing.service.ts
@@ -297,11 +297,13 @@ export class RemoteOpsProcessingService {
       );
     }
 
-    // Store operations with pending status before applying
+    // Store operations with pending status before applying (single transaction for performance)
     // If we crash after storing but before applying, these will be retried on startup
-    for (const op of opsToApply) {
-      const seq = await this.opLogStore.append(op, 'remote', { pendingApply: true });
-      opIdToSeq.set(op.id, seq);
+    if (opsToApply.length > 0) {
+      const seqs = await this.opLogStore.appendBatch(opsToApply, 'remote', {
+        pendingApply: true,
+      });
+      opsToApply.forEach((op, i) => opIdToSeq.set(op.id, seqs[i]));
     }
 
     // Apply only NON-duplicate ops to NgRx store