diff --git a/src/Glassboxx/Request/CustomerRequest.php b/src/Glassboxx/Request/CustomerRequest.php
index d60d92d..e3f8d75 100644
--- a/src/Glassboxx/Request/CustomerRequest.php
+++ b/src/Glassboxx/Request/CustomerRequest.php
@@ -7,19 +7,14 @@ namespace Opdavies\Glassboxx\Request;
 use Opdavies\Glassboxx\Traits\UsesAuthTokenTrait;
 use Opdavies\Glassboxx\ValueObject\CustomerInterface;
 
-final class CustomerRequest extends AbstractRequest
+final class CustomerRequest extends AbstractRequest implements CustomerRequestInterface
 {
     use UsesAuthTokenTrait;
 
-    public const ENDPOINT = '/glassboxxorder/customCustomer';
-
-    /** @var string */
-    protected $authToken;
-
     /** @var CustomerInterface */
     protected $customer;
 
-    public function forCustomer(CustomerInterface $customer): self
+    public function forCustomer(CustomerInterface $customer): AbstractRequest
     {
         $this->customer = $customer;
 
diff --git a/src/Glassboxx/Request/CustomerRequestInterface.php b/src/Glassboxx/Request/CustomerRequestInterface.php
new file mode 100644
index 0000000..2586988
--- /dev/null
+++ b/src/Glassboxx/Request/CustomerRequestInterface.php
@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Opdavies\Glassboxx\Request;
+
+use Opdavies\Glassboxx\ValueObject\CustomerInterface;
+
+interface CustomerRequestInterface
+{
+    public const ENDPOINT = '/glassboxxorder/customCustomer';
+
+    public function forCustomer(CustomerInterface $customer): AbstractRequest;
+
+    public function execute(): string;
+}
diff --git a/src/Glassboxx/Traits/UsesAuthTokenTrait.php b/src/Glassboxx/Traits/UsesAuthTokenTrait.php
index e68378e..81f441b 100644
--- a/src/Glassboxx/Traits/UsesAuthTokenTrait.php
+++ b/src/Glassboxx/Traits/UsesAuthTokenTrait.php
@@ -6,6 +6,8 @@ namespace Opdavies\Glassboxx\Traits;
 
 trait UsesAuthTokenTrait
 {
+    protected $authToken;
+
     public function withAuthToken(string $authToken): self
     {
         $this->authToken = $authToken;