diff --git a/src/Glassboxx/Request/AbstractRequest.php b/src/Glassboxx/Request/AbstractRequest.php
index a51cc3d..63dd206 100644
--- a/src/Glassboxx/Request/AbstractRequest.php
+++ b/src/Glassboxx/Request/AbstractRequest.php
@@ -15,7 +15,7 @@ abstract class AbstractRequest
 
     public const BASE_URL = 'https://server.glassboxx.co.uk';
 
-    /** @var HttpClient */
+    /** @var HttpClientInterface */
     protected $client;
 
     public function __construct(HttpClientInterface $client = null)
diff --git a/src/Glassboxx/Request/AuthTokenRequest.php b/src/Glassboxx/Request/AuthTokenRequest.php
index 5333214..0cf72ea 100644
--- a/src/Glassboxx/Request/AuthTokenRequest.php
+++ b/src/Glassboxx/Request/AuthTokenRequest.php
@@ -4,10 +4,16 @@ declare(strict_types=1);
 
 namespace Opdavies\Glassboxx\Request;
 
+use RuntimeException;
+
 final class AuthTokenRequest extends AbstractRequest implements AuthTokenRequestInterface
 {
     public function getToken(): string
     {
+        if (!$this->config) {
+            throw new RuntimeException('There is no config');
+        }
+
         $response = $this->client->request(
             'POST',
             self::ENDPOINT,
diff --git a/src/Glassboxx/Request/CustomerRequest.php b/src/Glassboxx/Request/CustomerRequest.php
index d290060..953189e 100644
--- a/src/Glassboxx/Request/CustomerRequest.php
+++ b/src/Glassboxx/Request/CustomerRequest.php
@@ -6,12 +6,13 @@ namespace Opdavies\Glassboxx\Request;
 
 use Opdavies\Glassboxx\Traits\UsesAuthTokenTrait;
 use Opdavies\Glassboxx\ValueObject\CustomerInterface;
+use RuntimeException;
 
 final class CustomerRequest extends AbstractRequest implements CustomerRequestInterface
 {
     use UsesAuthTokenTrait;
 
-    /** @var CustomerInterface */
+    /** @var CustomerInterface|null */
     protected $customer;
 
     public function forCustomer(CustomerInterface $customer): AbstractRequest
@@ -23,6 +24,14 @@ final class CustomerRequest extends AbstractRequest implements CustomerRequestIn
 
     public function execute(): string
     {
+        if (!$this->config) {
+            throw new RuntimeException('There is no config');
+        }
+
+        if (!$this->customer) {
+            throw new RuntimeException('There is no customer');
+        }
+
         $body = [
             'customer' => [
                 'created_in' => $this->config->getVendorId(),
diff --git a/src/Glassboxx/Request/OrderRequest.php b/src/Glassboxx/Request/OrderRequest.php
index ee6bb2c..428ece2 100644
--- a/src/Glassboxx/Request/OrderRequest.php
+++ b/src/Glassboxx/Request/OrderRequest.php
@@ -8,13 +8,14 @@ use Opdavies\Glassboxx\Enum\InteractionType;
 use Opdavies\Glassboxx\Traits\UsesAuthTokenTrait;
 use Opdavies\Glassboxx\Traits\UsesCreatedAtTrait;
 use Opdavies\Glassboxx\ValueObject\OrderInterface;
+use RuntimeException;
 
 class OrderRequest extends AbstractRequest implements OrderRequestInterface
 {
     use UsesCreatedAtTrait;
     use UsesAuthTokenTrait;
 
-    /** @var OrderInterface */
+    /** @var OrderInterface|null */
     private $order;
 
     public function forOrder(OrderInterface $order): AbstractRequest
@@ -26,6 +27,18 @@ class OrderRequest extends AbstractRequest implements OrderRequestInterface
 
     public function execute(): string
     {
+        if (!$this->config) {
+            throw new RuntimeException('There is no config');
+        }
+
+        if (!$this->order) {
+            throw new RuntimeException('There is no order');
+        }
+
+        if (!$this->order->getCustomer()) {
+            throw new RuntimeException('There is no customer');
+        }
+
         $body = [
             'items' => [
                 [
diff --git a/src/Glassboxx/Traits/UsesAuthTokenTrait.php b/src/Glassboxx/Traits/UsesAuthTokenTrait.php
index 81f441b..9117a26 100644
--- a/src/Glassboxx/Traits/UsesAuthTokenTrait.php
+++ b/src/Glassboxx/Traits/UsesAuthTokenTrait.php
@@ -6,6 +6,7 @@ namespace Opdavies\Glassboxx\Traits;
 
 trait UsesAuthTokenTrait
 {
+    /** @var string|null */
     protected $authToken;
 
     public function withAuthToken(string $authToken): self
diff --git a/src/Glassboxx/Traits/UsesConfigTrait.php b/src/Glassboxx/Traits/UsesConfigTrait.php
index dad7f0f..801f1bd 100644
--- a/src/Glassboxx/Traits/UsesConfigTrait.php
+++ b/src/Glassboxx/Traits/UsesConfigTrait.php
@@ -8,7 +8,7 @@ use Opdavies\Glassboxx\Config;
 
 trait UsesConfigTrait
 {
-    /** @var Config */
+    /** @var Config|null */
     protected $config;
 
     public function withConfig(Config $config): self