diff --git a/src/sdkClient/__tests__/clientAttributesDecoration.spec.ts b/src/sdkClient/__tests__/clientAttributesDecoration.spec.ts
new file mode 100644
index 00000000..bb6c0df7
--- /dev/null
+++ b/src/sdkClient/__tests__/clientAttributesDecoration.spec.ts
@@ -0,0 +1,211 @@
+import { clientAttributesDecoration } from '../clientAttributesDecoration';
+import { loggerMock } from '../../logger/__tests__/sdkLogger.mock';
+
+// mocked methods return the provided attributes object (2nd argument), to assert that it was properly passed
+const clientMock = {
+  getTreatment(maybeKey: any, maybeSplit: string, maybeAttributes?: any) {
+    return maybeAttributes;
+  },
+  getTreatmentWithConfig(maybeKey: any, maybeSplit: string, maybeAttributes?: any) {
+    return maybeAttributes;
+  },
+  getTreatments(maybeKey: any, maybeSplits: string[], maybeAttributes?: any) {
+    return maybeAttributes;
+  },
+  getTreatmentsWithConfig(maybeKey: any, maybeSplits: string[], maybeAttributes?: any) {
+    return maybeAttributes;
+  }
+};
+// @ts-expect-error
+const client = clientAttributesDecoration(loggerMock, clientMock);
+
+test('ATTRIBUTES DECORATION / storage', () => {
+
+  client.setAttribute('attributeName1', 'attributeValue1');
+  client.setAttribute('attributeName2', 'attributeValue2');
+
+  expect(client.getAttributes()).toEqual({ attributeName1: 'attributeValue1', attributeName2: 'attributeValue2' }); // It should be equal
+
+  client.removeAttribute('attributeName1');
+  client.setAttribute('attributeName2', 'newAttributeValue2');
+
+  expect(client.getAttribute('attributeName1')).toEqual(undefined); // It should throw undefined
+  expect(client.getAttribute('attributeName2')).toEqual('newAttributeValue2'); // It should be equal
+
+  client.setAttributes({
+    'attributeName3': 'attributeValue3',
+    'attributeName4': 'attributeValue4'
+  });
+
+  expect(client.getAttributes()).toEqual({ attributeName2: 'newAttributeValue2', attributeName3: 'attributeValue3', attributeName4: 'attributeValue4' }); // It should be equal
+
+  expect(client.clearAttributes()).toEqual(true);
+
+  expect(Object.keys(client.getAttributes()).length).toEqual(0); // It should be zero after clearing attributes
+
+});
+
+
+describe('ATTRIBUTES DECORATION / validation', () => {
+
+  test('Should return true if it is a valid attributes map without logging any errors', () => {
+    const validAttributes = { amIvalid: 'yes', 'are_you_sure': true, howMuch: 10, 'spell': ['1', '0'] };
+
+    expect(client.setAttributes(validAttributes)).toEqual(true); // It should return true if it is valid.
+    expect(client.getAttributes()).toEqual(validAttributes); // It should be the same.
+    expect(client.setAttribute('attrKey', 'attrValue')).toEqual(true); // It should return true.
+    expect(client.getAttribute('attrKey')).toEqual('attrValue'); // It should return true.
+
+    expect(client.removeAttribute('attrKey')).toEqual(true); // It should return true.
+    expect(client.getAttributes()).toEqual(validAttributes); // It should be equal to the first set.
+
+    expect(client.clearAttributes()).toEqual(true);
+
+    expect(Object.keys(client.getAttributes()).length).toEqual(0); // It should be zero after clearing attributes
+
+  });
+
+  test('Should return false if it is an invalid attributes map', () => {
+    expect(client.setAttribute('', 'attributeValue')).toEqual(false); // It should be invalid if the attribute key is not a string
+    expect(client.setAttribute('attributeKey1', new Date())).toEqual(false); // It should be invalid if the attribute value is not a String, Number, Boolean or Lists.
+    expect(client.setAttribute('attributeKey2', { 'some': 'object' })).toEqual(false); // It should be invalid if the attribute value is not a String, Number, Boolean or Lists.
+    expect(client.setAttribute('attributeKey3', Infinity)).toEqual(false); // It should be invalid if the attribute value is not a String, Number, Boolean or Lists.
+
+    expect(client.clearAttributes()).toEqual(true);
+
+    let values = client.getAttributes();
+
+    expect(Object.keys(values).length).toEqual(0); // It should be zero after clearing attributes
+
+    let attributes = {
+      'attributeKey': 'attributeValue',
+      '': 'attributeValue'
+    };
+
+    expect(client.setAttributes(attributes)).toEqual(false); // It should be invalid if the attribute key is not a string
+
+    expect(Object.keys(client.getAttributes()).length).toEqual(0); // It should be zero after trying to add an invalid attribute
+
+    expect(client.clearAttributes()).toEqual(true);
+
+  });
+
+  test('Should return true if attributes map is valid', () => {
+    const validAttributes = {
+      'attributeKey1': 'attributeValue',
+      'attributeKey2': ['attribute', 'value'],
+      'attributeKey3': 25,
+      'attributeKey4': false
+    };
+
+    expect(client.setAttribute('attributeKey1', 'attributeValue')).toEqual(true); // It should be valid if the attribute value is a String, Number, Boolean or Lists.
+    expect(client.setAttribute('attributeKey2', ['attribute', 'value'])).toEqual(true); // It should be valid if the attribute value is a String, Number, Boolean or Lists.
+    expect(client.setAttribute('attributeKey3', 25)).toEqual(true); // It should be valid if the attribute value is a String, Number, Boolean or Lists.
+    expect(client.setAttribute('attributeKey4', false)).toEqual(true); // It should be valid if the attribute value is a String, Number, Boolean or Lists.
+    expect(client.setAttribute('attributeKey5', Date.now())).toEqual(true); // It should be valid if the attribute value is a String, Number, Boolean or Lists.
+
+    expect(client.removeAttribute('attributeKey5')).toEqual(true); // It should be capable of remove the attribute with that name
+    expect(client.getAttributes()).toEqual(validAttributes); // It should had stored every valid attributes.
+
+    expect(client.clearAttributes()).toEqual(true);
+
+    expect(client.setAttributes(validAttributes)).toEqual(true); // It should add them all because they are valid attributes.
+    expect(client.getAttributes()).toEqual(validAttributes); // It should had stored every valid attributes.
+
+    expect(client.clearAttributes()).toEqual(true);
+
+  });
+
+});
+
+describe('ATTRIBUTES DECORATION / evaluation', () => {
+
+  test('Evaluation attributes logic and precedence / getTreatment', () => {
+
+    // If the same attribute is “cached” and provided on the function, the value received on the function call takes precedence.
+    expect(client.getTreatment('key', 'split')).toEqual(undefined); // Nothing changes if no attributes were provided using the new api
+    expect(client.getTreatment('key', 'split', { func_attr_bool: true, func_attr_str: 'true' })).toEqual({ func_attr_bool: true, func_attr_str: 'true' }); // Nothing changes if no attributes were provided using the new api
+    expect(client.getAttributes()).toEqual({}); // Attributes in memory storage must be empty
+    client.setAttribute('func_attr_bool', false);
+    expect(client.getAttributes()).toEqual({ 'func_attr_bool': false }); // In memory attribute storage must have the unique stored attribute
+    expect(client.getTreatment('key', 'split', { func_attr_bool: true, func_attr_str: 'true' })).toEqual({ func_attr_bool: true, func_attr_str: 'true' }); // Function attributes has precedence against api ones
+    // @ts-ignore
+    expect(client.getTreatment('key', 'split', null)).toEqual({ func_attr_bool: false }); // API attributes should be kept in memory and use for evaluations
+    expect(client.getTreatment('key', 'split', { func_attr_str: 'true' })).toEqual({ func_attr_bool: false, func_attr_str: 'true' }); // API attributes should be kept in memory and use for evaluations
+    client.setAttributes({ func_attr_str: 'false' });
+    expect(client.getAttributes()).toEqual({ 'func_attr_bool': false, 'func_attr_str': 'false' }); // In memory attribute storage must have two stored attributes
+    expect(client.getTreatment('key', 'split', { func_attr_bool: true, func_attr_str: 'true', func_attr_number: 1 })).toEqual({ func_attr_bool: true, func_attr_str: 'true', func_attr_number: 1 }); // Function attributes has precedence against api ones
+    // @ts-ignore
+    expect(client.getTreatment('key', 'split', null)).toEqual({ func_attr_bool: false, func_attr_str: 'false' }); // If the getTreatment function is called without attributes, stored attributes will be used to evaluate.
+    expect(client.getTreatment('key', 'split')).toEqual({ func_attr_bool: false, func_attr_str: 'false' }); // If the getTreatment function is called without attributes, stored attributes will be used to evaluate.
+    expect(client.clearAttributes()).toEqual(true);
+
+  });
+
+  test('Evaluation attributes logic and precedence / getTreatments', () => {
+
+    // If the same attribute is “cached” and provided on the function, the value received on the function call takes precedence.
+    expect(client.getTreatments('key', ['split'])).toEqual(undefined); // Nothing changes if no attributes were provided using the new api
+    expect(client.getTreatments('key', ['split'], { func_attr_bool: true, func_attr_str: 'true' })).toEqual({ func_attr_bool: true, func_attr_str: 'true' }); // Nothing changes if no attributes were provided using the new api
+    expect(client.getAttributes()).toEqual({}); // Attributes in memory storage must be empty
+    client.setAttribute('func_attr_bool', false);
+    expect(client.getAttributes()).toEqual({ 'func_attr_bool': false }); // In memory attribute storage must have the unique stored attribute
+    expect(client.getTreatments('key', ['split'], { func_attr_bool: true, func_attr_str: 'true' })).toEqual({ func_attr_bool: true, func_attr_str: 'true' }); // Function attributes has precedence against api ones
+    // @ts-ignore
+    expect(client.getTreatments('key', ['split'], null)).toEqual({ func_attr_bool: false }); // API attributes should be kept in memory and use for evaluations
+    expect(client.getTreatments('key', ['split'], { func_attr_str: 'true' })).toEqual({ func_attr_bool: false, func_attr_str: 'true' }); // API attributes should be kept in memory and use for evaluations
+    client.setAttributes({ func_attr_str: 'false' });
+    expect(client.getAttributes()).toEqual({ 'func_attr_bool': false, 'func_attr_str': 'false' }); // In memory attribute storage must have two stored attributes
+    expect(client.getTreatments('key', ['split'], { func_attr_bool: true, func_attr_str: 'true', func_attr_number: 1 })).toEqual({ func_attr_bool: true, func_attr_str: 'true', func_attr_number: 1 }); // Function attributes has precedence against api ones
+    // @ts-ignore
+    expect(client.getTreatments('key', ['split'], null)).toEqual({ func_attr_bool: false, func_attr_str: 'false' }); // If the getTreatment function is called without attributes, stored attributes will be used to evaluate.
+    expect(client.getTreatments('key', ['split'])).toEqual({ func_attr_bool: false, func_attr_str: 'false' }); // If the getTreatment function is called without attributes, stored attributes will be used to evaluate.
+    expect(client.clearAttributes()).toEqual(true);
+
+  });
+
+  test('Evaluation attributes logic and precedence / getTreatmentWithConfig', () => {
+
+    // If the same attribute is “cached” and provided on the function, the value received on the function call takes precedence.
+    expect(client.getTreatmentWithConfig('key', 'split')).toEqual(undefined); // Nothing changes if no attributes were provided using the new api
+    expect(client.getTreatmentWithConfig('key', 'split', { func_attr_bool: true, func_attr_str: 'true' })).toEqual({ func_attr_bool: true, func_attr_str: 'true' }); // Nothing changes if no attributes were provided using the new api
+    expect(client.getAttributes()).toEqual({}); // Attributes in memory storage must be empty
+    client.setAttribute('func_attr_bool', false);
+    expect(client.getAttributes()).toEqual({ 'func_attr_bool': false }); // In memory attribute storage must have the unique stored attribute
+    expect(client.getTreatmentWithConfig('key', 'split', { func_attr_bool: true, func_attr_str: 'true' })).toEqual({ func_attr_bool: true, func_attr_str: 'true' }); // Function attributes has precedence against api ones
+    // @ts-ignore
+    expect(client.getTreatmentWithConfig('key', 'split', null)).toEqual({ func_attr_bool: false }); // API attributes should be kept in memory and use for evaluations
+    expect(client.getTreatmentWithConfig('key', 'split', { func_attr_str: 'true' })).toEqual({ func_attr_bool: false, func_attr_str: 'true' }); // API attributes should be kept in memory and use for evaluations
+    client.setAttributes({ func_attr_str: 'false' });
+    expect(client.getAttributes()).toEqual({ 'func_attr_bool': false, 'func_attr_str': 'false' }); // In memory attribute storage must have two stored attributes
+    expect(client.getTreatmentWithConfig('key', 'split', { func_attr_bool: true, func_attr_str: 'true', func_attr_number: 1 })).toEqual({ func_attr_bool: true, func_attr_str: 'true', func_attr_number: 1 }); // Function attributes has precedence against api ones
+    // @ts-ignore
+    expect(client.getTreatmentWithConfig('key', 'split', null)).toEqual({ func_attr_bool: false, func_attr_str: 'false' }); // If the getTreatment function is called without attributes, stored attributes will be used to evaluate.
+    expect(client.getTreatmentWithConfig('key', 'split')).toEqual({ func_attr_bool: false, func_attr_str: 'false' }); // If the getTreatment function is called without attributes, stored attributes will be used to evaluate.
+    expect(client.clearAttributes()).toEqual(true);
+
+  });
+
+  test('Evaluation attributes logic and precedence / getTreatmentsWithConfig', () => {
+
+    // If the same attribute is “cached” and provided on the function, the value received on the function call takes precedence.
+    expect(client.getTreatmentsWithConfig('key', ['split'])).toEqual(undefined); // Nothing changes if no attributes were provided using the new api
+    expect(client.getTreatmentsWithConfig('key', ['split'], { func_attr_bool: true, func_attr_str: 'true' })).toEqual({ func_attr_bool: true, func_attr_str: 'true' }); // Nothing changes if no attributes were provided using the new api
+    expect(client.getAttributes()).toEqual({}); // Attributes in memory storage must be empty
+    client.setAttribute('func_attr_bool', false);
+    expect(client.getAttributes()).toEqual({ 'func_attr_bool': false }); // In memory attribute storage must have the unique stored attribute
+    expect(client.getTreatmentsWithConfig('key', ['split'], { func_attr_bool: true, func_attr_str: 'true' })).toEqual({ func_attr_bool: true, func_attr_str: 'true' }); // Function attributes has precedence against api ones
+    // @ts-ignore
+    expect(client.getTreatmentsWithConfig('key', ['split'], null)).toEqual({ func_attr_bool: false }); // API attributes should be kept in memory and use for evaluations
+    expect(client.getTreatmentsWithConfig('key', ['split'], { func_attr_str: 'true' })).toEqual({ func_attr_bool: false, func_attr_str: 'true' }); // API attributes should be kept in memory and use for evaluations
+    client.setAttributes({ func_attr_str: 'false' });
+    expect(client.getAttributes()).toEqual({ 'func_attr_bool': false, 'func_attr_str': 'false' }); // In memory attribute storage must have two stored attributes
+    expect(client.getTreatmentsWithConfig('key', ['split'], { func_attr_bool: true, func_attr_str: 'true', func_attr_number: 1 })).toEqual({ func_attr_bool: true, func_attr_str: 'true', func_attr_number: 1 }); // Function attributes has precedence against api ones
+    // @ts-ignore
+    expect(client.getTreatmentsWithConfig('key', ['split'], null)).toEqual({ func_attr_bool: false, func_attr_str: 'false' }); // If the getTreatment function is called without attributes, stored attributes will be used to evaluate.
+    expect(client.getTreatmentsWithConfig('key', ['split'])).toEqual({ func_attr_bool: false, func_attr_str: 'false' }); // If the getTreatment function is called without attributes, stored attributes will be used to evaluate.
+    client.clearAttributes();
+
+  });
+
+});
diff --git a/src/sdkClient/clientAttributesDecoration.ts b/src/sdkClient/clientAttributesDecoration.ts
index e4ff1270..5d55c7df 100644
--- a/src/sdkClient/clientAttributesDecoration.ts
+++ b/src/sdkClient/clientAttributesDecoration.ts
@@ -7,7 +7,7 @@ import { objectAssign } from '../utils/lang/objectAssign';
 /**
  * Add in memory attributes storage methods and combine them with any attribute received from the getTreatment/s call 
  */
-export function clientAttributesDecoration<TClient extends SplitIO.IClient | SplitIO.IAsyncClient>(log: ILogger, client: TClient): any {
+export function clientAttributesDecoration<TClient extends SplitIO.IClient | SplitIO.IAsyncClient>(log: ILogger, client: TClient) {
 
   const attributeStorage = new AttributesCacheInMemory();
 
@@ -19,25 +19,33 @@ export function clientAttributesDecoration<TClient extends SplitIO.IClient | Spl
   const clientTrack = client.track;
 
   function getTreatment(maybeKey: SplitIO.SplitKey, maybeSplit: string, maybeAttributes?: SplitIO.Attributes) {
-    return clientGetTreatment(maybeKey, maybeSplit, maybeAttributes);
+    return clientGetTreatment(maybeKey, maybeSplit, combineAttributes(maybeAttributes));
   }
 
   function getTreatmentWithConfig(maybeKey: SplitIO.SplitKey, maybeSplit: string, maybeAttributes?: SplitIO.Attributes) {
-    return clientGetTreatmentWithConfig(maybeKey, maybeSplit, maybeAttributes);
+    return clientGetTreatmentWithConfig(maybeKey, maybeSplit, combineAttributes(maybeAttributes));
   }
 
   function getTreatments(maybeKey: SplitIO.SplitKey, maybeSplits: string[], maybeAttributes?: SplitIO.Attributes) {
-    return clientGetTreatments(maybeKey, maybeSplits, maybeAttributes);
+    return clientGetTreatments(maybeKey, maybeSplits, combineAttributes(maybeAttributes));
   }
 
   function getTreatmentsWithConfig(maybeKey: SplitIO.SplitKey, maybeSplits: string[], maybeAttributes?: SplitIO.Attributes) {
-    return clientGetTreatmentsWithConfig(maybeKey, maybeSplits, maybeAttributes);
+    return clientGetTreatmentsWithConfig(maybeKey, maybeSplits, combineAttributes(maybeAttributes));
   }
 
   function track(maybeKey: SplitIO.SplitKey, maybeTT: string, maybeEvent: string, maybeEventValue?: number, maybeProperties?: SplitIO.Properties) {
     return clientTrack(maybeKey, maybeTT, maybeEvent, maybeEventValue, maybeProperties);
   }
 
+  function combineAttributes(maybeAttributes: SplitIO.Attributes | undefined): SplitIO.Attributes | undefined{
+    const storedAttributes = attributeStorage.getAll();
+    if (Object.keys(storedAttributes).length > 0) {
+      return objectAssign({}, storedAttributes, maybeAttributes);
+    }
+    return maybeAttributes;
+  }
+
   return objectAssign(client, {
     getTreatment: getTreatment,
     getTreatmentWithConfig: getTreatmentWithConfig,