diff --git a/src/Zendesk/API/HttpClient.php b/src/Zendesk/API/HttpClient.php
index d38e2e79b..0d8dcfeb0 100644
--- a/src/Zendesk/API/HttpClient.php
+++ b/src/Zendesk/API/HttpClient.php
@@ -58,6 +58,7 @@
 use Zendesk\API\Resources\HelpCenter;
 use Zendesk\API\Resources\Talk;
 use Zendesk\API\Resources\Voice;
+use Zendesk\API\Resources\Sell;
 use Zendesk\API\Traits\Utility\InstantiatorTrait;
 use Zendesk\API\Utilities\Auth;
 
@@ -185,6 +186,11 @@ class HttpClient
      */
     public $talk;
 
+    /**
+     * @var Sell
+     */
+    public $sell;
+
     /**
      * @param string $subdomain
      * @param string $username
@@ -229,6 +235,7 @@ public function __construct(
         $this->embeddable = new Embeddable($this);
         $this->chat       = new Chat($this);
         $this->talk       = new Talk($this);
+        $this->sell       = new Sell($this);
     }
 
     /**
diff --git a/src/Zendesk/API/Resources/Sell.php b/src/Zendesk/API/Resources/Sell.php
new file mode 100644
index 000000000..586e842da
--- /dev/null
+++ b/src/Zendesk/API/Resources/Sell.php
@@ -0,0 +1,42 @@
+<?php
+
+namespace Zendesk\API\Resources;
+
+use Zendesk\API\HttpClient;
+use Zendesk\API\Resources\Sell\Contacts;
+use Zendesk\API\Traits\Utility\ChainedParametersTrait;
+use Zendesk\API\Traits\Utility\InstantiatorTrait;
+
+/**
+ * This class serves as a container to allow $this->client->sell
+ *
+ * @method Contacts contacts()
+ */
+class Sell
+{
+    use ChainedParametersTrait;
+    use InstantiatorTrait;
+
+    public $client;
+
+    /**
+     * Sets the client to be used
+     *
+     * @param HttpClient $client
+     */
+    public function __construct(HttpClient $client)
+    {
+        $this->client = $client;
+    }
+
+    /**
+     * @inheritdoc
+     * @return array
+     */
+    public static function getValidSubResources()
+    {
+        return [
+            'contacts' => Contacts::class,
+        ];
+    }
+}
diff --git a/src/Zendesk/API/Resources/Sell/Contacts.php b/src/Zendesk/API/Resources/Sell/Contacts.php
new file mode 100644
index 000000000..1bf7fcf17
--- /dev/null
+++ b/src/Zendesk/API/Resources/Sell/Contacts.php
@@ -0,0 +1,62 @@
+<?php
+
+namespace Zendesk\API\Resources\Sell;
+
+use Zendesk\API\Traits\Resource\Defaults;
+use Zendesk\API\Traits\Utility\InstantiatorTrait;
+
+/**
+ * Contacts class provides a simple interface to manage your contacts in Sell
+ * https://developers.getbase.com/docs/rest/reference/contacts
+ */
+class Contacts extends ResourceAbstract
+{
+    use InstantiatorTrait;
+    use Defaults;
+
+    /**
+     * {@inheritdoc}
+     */
+    protected $objectName = 'data';
+
+    /**
+     * {@inheritdoc}
+     */
+    protected $resourceName = 'contacts';
+
+    /**
+     * Declares routes to be used by this resource.
+     */
+    protected function setUpRoutes()
+    {
+        parent::setUpRoutes();
+
+        $this->setRoutes([
+            "find"    => "{$this->resourceName}/{id}",
+            "findAll" => $this->resourceName,
+            "create"  => $this->resourceName,
+            "update"  => "{$this->resourceName}/{id}",
+            "delete"  => "{$this->resourceName}/{id}",
+            "upsert"  => "{$this->resourceName}/upsert",
+        ]);
+    }
+
+    /**
+     * Create a new contact or update an existing, based on a value of a filter or a set of filters
+     * @param array $params
+     * @param array $updateResourceFields
+     * @return \stdClass|null
+     * @throws \Zendesk\API\Exceptions\ApiResponseException
+     * @throws \Zendesk\API\Exceptions\AuthException
+     */
+    public function upsert(array $params, array $updateResourceFields)
+    {
+        $route = $this->getRoute(__FUNCTION__);
+
+        return $this->client->post(
+            $route,
+            [$this->objectName => $updateResourceFields],
+            ['queryParams' => $params]
+        );
+    }
+}
diff --git a/src/Zendesk/API/Resources/Sell/ResourceAbstract.php b/src/Zendesk/API/Resources/Sell/ResourceAbstract.php
new file mode 100644
index 000000000..928f90006
--- /dev/null
+++ b/src/Zendesk/API/Resources/Sell/ResourceAbstract.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace Zendesk\API\Resources\Sell;
+
+/**
+ * Abstract class for Sell resources
+ */
+abstract class ResourceAbstract extends \Zendesk\API\Resources\ResourceAbstract
+{
+    protected $apiBasePath = 'v2/';
+}
diff --git a/tests/Zendesk/API/UnitTests/Sell/ContactsTest.php b/tests/Zendesk/API/UnitTests/Sell/ContactsTest.php
new file mode 100644
index 000000000..c5539b6d4
--- /dev/null
+++ b/tests/Zendesk/API/UnitTests/Sell/ContactsTest.php
@@ -0,0 +1,51 @@
+<?php
+
+namespace Zendesk\API\UnitTests\Sell;
+
+use Faker\Factory;
+use Zendesk\API\UnitTests\BasicTest;
+
+class ContactsTest extends BasicTest
+{
+
+    /**
+     * Test that the correct traits were added by checking the available methods
+     */
+    public function testMethods()
+    {
+        $this->assertTrue(method_exists($this->client->sell->contacts(), 'create'));
+        $this->assertTrue(method_exists($this->client->sell->contacts(), 'delete'));
+        $this->assertTrue(method_exists($this->client->sell->contacts(), 'find'));
+        $this->assertTrue(method_exists($this->client->sell->contacts(), 'findAll'));
+        $this->assertTrue(method_exists($this->client->sell->contacts(), 'update'));
+        $this->assertTrue(method_exists($this->client->sell->contacts(), 'upsert'));
+    }
+
+    /**
+     * Tests if the upsert endpoint can be called and passed the correct params
+     */
+    public function testUpsert()
+    {
+        $faker = Factory::create();
+
+        $queryParams = [
+            'email' => $faker->email,
+            'phone' => $faker->phoneNumber,
+        ];
+
+        $postFields = [
+            'email'         => $faker->email,
+            'custom_fields' => [
+                'Some Field' => $faker->text
+            ]
+        ];
+
+        $this->assertEndpointCalled(function () use ($queryParams, $postFields) {
+            $this->client->sell->contacts()->upsert($queryParams, $postFields);
+        }, '/contacts/upsert', 'POST', [
+            'queryParams' => $queryParams,
+            'postFields'  => ['data' => $postFields],
+            'apiBasePath' => '/v2'
+        ]);
+    }
+}