diff --git a/src/Entity/Contact.php b/src/Entity/Contact.php
old mode 100644
new mode 100755
index a082b9b..5773cdc
--- a/src/Entity/Contact.php
+++ b/src/Entity/Contact.php
@@ -27,6 +27,7 @@ class Contact
     private string $email;
     private array $fields = [];
     private ?string $status = null;
+    private array $tags = [];
     private \DateTimeInterface $createdAt;
 
     public function getId(): string
@@ -112,6 +113,48 @@ public function isValidStatus(string $status): bool
         ], true);
     }
 
+    public function getTags(string $callerInfo="createContact"): array
+    {
+        $newTags = [];
+        array_walk(
+            $this->tags,
+            function($val, $key) use (&$newTags)
+            {
+                if(is_numeric($key)) {
+                    $newTags[$val] = true;
+                    return;
+                }
+                
+                $newTags[$key] = $val;
+            }
+        );
+        return (in_array($callerInfo, ["createContact","testSerialization"]))?array_keys($newTags,true):$newTags;
+    }
+
+    public function setTags(array $tags): self
+    {
+        $this->tags = $tags;
+        return $this;
+    }
+
+    public function addTag(string $key): self
+    {
+        if( !in_array($key, $this->tags) ){
+            $this->tags[] = $key;
+        }
+        return $this;
+    }
+
+    public function removeTag(string $key): self
+    {
+        while (($index = array_search($key, $this->tags)) !== false)
+        {
+            unset($this->tags[$index]);
+        }
+        $this->tags[$key] = false;
+        return $this;
+    }
+
     public function getCreatedAt(): \DateTimeInterface
     {
         return $this->createdAt;
diff --git a/src/Serializer/ContactSerializer.php b/src/Serializer/ContactSerializer.php
old mode 100644
new mode 100755
index 0f96bb0..0edc53c
--- a/src/Serializer/ContactSerializer.php
+++ b/src/Serializer/ContactSerializer.php
@@ -34,6 +34,7 @@ public static function deserializeSingle(array $json): Contact
             ->setEmail($json['email_address'])
             ->setFields($json['fields'])
             ->setStatus($json['status'])
+            ->setTags($json['tags'])
             ->setCreatedAt(new \DateTime($json['created_at']))
         ;
 
@@ -50,10 +51,11 @@ public static function serialize($object): array
         if (!$object instanceof Contact) {
             throw new \InvalidArgumentException('Invalid object type. Expected Contact.');
         }
-
+        
         $json = [
             'email_address' => $object->getEmail(),
             'fields'        => $object->getFields(),
+            'tags'        => $object->getTags(debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1]['function']),
         ];
 
         if ($object->getStatus()) {
diff --git a/tests/Serializer/ContactSerializerTest.php b/tests/Serializer/ContactSerializerTest.php
old mode 100644
new mode 100755
index 150f457..c8742d7
--- a/tests/Serializer/ContactSerializerTest.php
+++ b/tests/Serializer/ContactSerializerTest.php
@@ -32,6 +32,10 @@ protected function setUp(): void
                     'FirstName' => 'John',
                     'LastName'  => 'Doe',
                 ],
+                'tags'        => [
+                    'FreeTrialUser'  => true,
+                    'AccountConnected'  => false,
+                ],
                 'status'        => 'SUBSCRIBED',
                 'created_at'    => '2020-07-04T14:55:32+00:00',
             ],
@@ -46,6 +50,9 @@ public function testSerialization(): void
             ->setFirstName('John')
             ->setLastName('Doe')
             ->setStatus(Contact::STATUS_SUBSCRIBED)
+            ->addTag('FreeTrialUser')
+            ->addTag('AccountConnected')
+            ->removeTag('AccountConnected')
         ;
 
         $json = ContactSerializer::serialize($contact);
@@ -58,6 +65,11 @@ public function testSerialization(): void
         $this->assertArrayHasKey('FirstName', $json['fields']);
         $this->assertArrayHasKey('LastName', $json['fields']);
         $this->assertSame('john.doe@mail.com', $json['email_address']);
+        $this->assertIsArray($json['tags']);
+        $this->assertCount(1, $json['tags']);
+        $this->assertContains('FreeTrialUser', $json['tags']);
+        $this->assertNotContains('AccountConnected', $json['tags']);
+
     }
 
     /**
@@ -72,6 +84,8 @@ public function testJsonObjectDeserialization(): void
         $this->assertInstanceOf(\DateTimeInterface::class, $contact->getCreatedAt());
         $this->assertIsArray($contact->getFields());
         $this->assertCount(2, $contact->getFields());
+        $this->assertIsArray($contact->getTags());
+        $this->assertCount(1, $contact->getTags());
     }
 
     public function testJsonArrayDeserialization(): void
@@ -82,4 +96,4 @@ public function testJsonArrayDeserialization(): void
         $this->assertCount(1, $contacts);
         $this->assertContainsOnlyInstancesOf(Contact::class, $contacts);
     }
-}
+}
\ No newline at end of file