diff --git a/src/storages/inMemory/SplitsCacheInMemory.ts b/src/storages/inMemory/SplitsCacheInMemory.ts
index 6c5ecb36..36a55fe1 100644
--- a/src/storages/inMemory/SplitsCacheInMemory.ts
+++ b/src/storages/inMemory/SplitsCacheInMemory.ts
@@ -16,9 +16,9 @@ export class SplitsCacheInMemory extends AbstractSplitsCacheSync {
   private splitsWithSegmentsCount: number = 0;
   private flagSetsCache: Record<string, ISet<string>> = {};
 
-  constructor(splitFiltersValidation: ISplitFiltersValidation = { queryString: null, groupedFilters: { bySet: [], byName: [], byPrefix: [] }, validFilters: [] }) {
+  constructor(splitFiltersValidation?: ISplitFiltersValidation) {
     super();
-    this.flagSetsFilter = splitFiltersValidation.groupedFilters.bySet;
+    this.flagSetsFilter = splitFiltersValidation ? splitFiltersValidation.groupedFilters.bySet : [];
   }
 
   clear() {
diff --git a/src/storages/pluggable/SplitsCachePluggable.ts b/src/storages/pluggable/SplitsCachePluggable.ts
index 8aa7da58..8f355fb1 100644
--- a/src/storages/pluggable/SplitsCachePluggable.ts
+++ b/src/storages/pluggable/SplitsCachePluggable.ts
@@ -2,7 +2,7 @@ import { isFiniteNumber, isNaNNumber } from '../../utils/lang';
 import { KeyBuilder } from '../KeyBuilder';
 import { IPluggableStorageWrapper } from '../types';
 import { ILogger } from '../../logger/types';
-import { ISplit } from '../../dtos/types';
+import { ISplit, ISplitFiltersValidation } from '../../dtos/types';
 import { LOG_PREFIX } from './constants';
 import { AbstractSplitsCacheAsync } from '../AbstractSplitsCacheAsync';
 import { ISet, _Set, returnListDifference } from '../../utils/lang/sets';
@@ -23,12 +23,12 @@ export class SplitsCachePluggable extends AbstractSplitsCacheAsync {
    * @param keys  Key builder.
    * @param wrapper  Adapted wrapper storage.
    */
-  constructor(log: ILogger, keys: KeyBuilder, wrapper: IPluggableStorageWrapper, flagSetsFilter: string[] = []) {
+  constructor(log: ILogger, keys: KeyBuilder, wrapper: IPluggableStorageWrapper, splitFiltersValidation?: ISplitFiltersValidation) {
     super();
     this.log = log;
     this.keys = keys;
     this.wrapper = wrapper;
-    this.flagSetsFilter = flagSetsFilter;
+    this.flagSetsFilter = splitFiltersValidation ? splitFiltersValidation.groupedFilters.bySet : [];
   }
 
   private _decrementCounts(split: ISplit) {
diff --git a/src/storages/pluggable/__tests__/SplitsCachePluggable.spec.ts b/src/storages/pluggable/__tests__/SplitsCachePluggable.spec.ts
index 6cad1e2a..3d67e454 100644
--- a/src/storages/pluggable/__tests__/SplitsCachePluggable.spec.ts
+++ b/src/storages/pluggable/__tests__/SplitsCachePluggable.spec.ts
@@ -2,8 +2,9 @@ import { SplitsCachePluggable } from '../SplitsCachePluggable';
 import { KeyBuilder } from '../../KeyBuilder';
 import { loggerMock } from '../../../logger/__tests__/sdkLogger.mock';
 import { wrapperMockFactory } from './wrapper.mock';
-import { splitWithUserTT, splitWithAccountTT } from '../../__tests__/testUtils';
+import { splitWithUserTT, splitWithAccountTT, featureFlagOne, featureFlagThree, featureFlagTwo, featureFlagWithEmptyFS, featureFlagWithoutFS } from '../../__tests__/testUtils';
 import { ISplit } from '../../../dtos/types';
+import { _Set } from '../../../utils/lang/sets';
 
 const keysBuilder = new KeyBuilder();
 
@@ -150,4 +151,63 @@ describe('SPLITS CACHE PLUGGABLE', () => {
     expect(await wrapper.getKeysByPrefix('SPLITIO')).toHaveLength(0);
   });
 
+  test('flag set cache tests', async () => {
+    // @ts-ignore
+    const cache = new SplitsCachePluggable(loggerMock, keysBuilder, wrapperMockFactory(), { groupedFilters: { bySet: ['o', 'n', 'e', 'x'] } });
+    const emptySet = new _Set([]);
+
+    await cache.addSplits([
+      [featureFlagOne.name, featureFlagOne],
+      [featureFlagTwo.name, featureFlagTwo],
+      [featureFlagThree.name, featureFlagThree],
+    ]);
+    await cache.addSplit(featureFlagWithEmptyFS.name, featureFlagWithEmptyFS);
+
+    expect(await cache.getNamesByFlagSets(['o'])).toEqual(new _Set(['ff_one', 'ff_two']));
+    expect(await cache.getNamesByFlagSets(['n'])).toEqual(new _Set(['ff_one']));
+    expect(await cache.getNamesByFlagSets(['e'])).toEqual(new _Set(['ff_one', 'ff_three']));
+    expect(await cache.getNamesByFlagSets(['t'])).toEqual(emptySet); // 't' not in filter
+    expect(await cache.getNamesByFlagSets(['o', 'n', 'e'])).toEqual(new _Set(['ff_one', 'ff_two', 'ff_three']));
+
+    await cache.addSplit(featureFlagOne.name, { ...featureFlagOne, sets: ['1'] });
+
+    expect(await cache.getNamesByFlagSets(['1'])).toEqual(emptySet); // '1' not in filter
+    expect(await cache.getNamesByFlagSets(['o'])).toEqual(new _Set(['ff_two']));
+    expect(await cache.getNamesByFlagSets(['n'])).toEqual(emptySet);
+
+    await cache.addSplit(featureFlagOne.name, { ...featureFlagOne, sets: ['x'] });
+    expect(await cache.getNamesByFlagSets(['x'])).toEqual(new _Set(['ff_one']));
+    expect(await cache.getNamesByFlagSets(['o', 'e', 'x'])).toEqual(new _Set(['ff_one', 'ff_two', 'ff_three']));
+
+    await cache.removeSplit(featureFlagOne.name);
+    expect(await cache.getNamesByFlagSets(['x'])).toEqual(emptySet);
+
+    await cache.removeSplit(featureFlagOne.name);
+    expect(await cache.getNamesByFlagSets(['y'])).toEqual(emptySet); // 'y' not in filter
+    expect(await cache.getNamesByFlagSets([])).toEqual(emptySet);
+
+    await cache.addSplit(featureFlagWithEmptyFS.name, featureFlagWithoutFS);
+    expect(await cache.getNamesByFlagSets([])).toEqual(emptySet);
+  });
+
+  // if FlagSets filter is not defined, it should store all FlagSets in memory.
+  test('flag set cache tests without filters', async () => {
+    const cacheWithoutFilters = new SplitsCachePluggable(loggerMock, keysBuilder, wrapperMockFactory());
+    const emptySet = new _Set([]);
+
+    await cacheWithoutFilters.addSplits([
+      [featureFlagOne.name, featureFlagOne],
+      [featureFlagTwo.name, featureFlagTwo],
+      [featureFlagThree.name, featureFlagThree],
+    ]);
+    await cacheWithoutFilters.addSplit(featureFlagWithEmptyFS.name, featureFlagWithEmptyFS);
+
+    expect(await cacheWithoutFilters.getNamesByFlagSets(['o'])).toEqual(new _Set(['ff_one', 'ff_two']));
+    expect(await cacheWithoutFilters.getNamesByFlagSets(['n'])).toEqual(new _Set(['ff_one']));
+    expect(await cacheWithoutFilters.getNamesByFlagSets(['e'])).toEqual(new _Set(['ff_one', 'ff_three']));
+    expect(await cacheWithoutFilters.getNamesByFlagSets(['t'])).toEqual(new _Set(['ff_two', 'ff_three']));
+    expect(await cacheWithoutFilters.getNamesByFlagSets(['y'])).toEqual(emptySet);
+    expect(await cacheWithoutFilters.getNamesByFlagSets(['o', 'n', 'e'])).toEqual(new _Set(['ff_one', 'ff_two', 'ff_three']));
+  });
+
 });
diff --git a/src/storages/pluggable/index.ts b/src/storages/pluggable/index.ts
index 93442b73..3e72d791 100644
--- a/src/storages/pluggable/index.ts
+++ b/src/storages/pluggable/index.ts
@@ -105,7 +105,7 @@ export function PluggableStorage(options: PluggableStorageOptions): IStorageAsyn
     });
 
     return {
-      splits: new SplitsCachePluggable(log, keys, wrapper, settings.sync.__splitFiltersValidation.groupedFilters.bySet),
+      splits: new SplitsCachePluggable(log, keys, wrapper, settings.sync.__splitFiltersValidation),
       segments: new SegmentsCachePluggable(log, keys, wrapper),
       impressions: isPartialConsumer ? new ImpressionsCacheInMemory(impressionsQueueSize) : new ImpressionsCachePluggable(log, keys.buildImpressionsKey(), wrapper, metadata),
       impressionCounts: impressionCountsCache,