diff --git a/src/Mailgun/Api/HttpApi.php b/src/Mailgun/Api/HttpApi.php
index 57dbdd6..67b7ca0 100644
--- a/src/Mailgun/Api/HttpApi.php
+++ b/src/Mailgun/Api/HttpApi.php
@@ -32,7 +32,7 @@ abstract class HttpApi
     /**
      * @var ResponseDeserializer
      */
-    protected $serializer;
+    protected $deserializer;
 
     /**
      * @var RequestBuilder
@@ -59,7 +59,7 @@ abstract class HttpApi
      * @param ResponseInterface $response
      * @param string            $className
      *
-     * @return $class|SimpleResponse
+     * @return object $class
      */
     protected function safeDeserialize(ResponseInterface $response, $className)
     {
diff --git a/src/Mailgun/Connection/RestClient.php b/src/Mailgun/Connection/RestClient.php
index d93a36b..63f160b 100644
--- a/src/Mailgun/Connection/RestClient.php
+++ b/src/Mailgun/Connection/RestClient.php
@@ -270,7 +270,6 @@ class RestClient
     protected function prepareFile($fieldName, $filePath, $fileIndex = 0)
     {
         $filename = null;
-        $resource = null;
 
         if (is_array($filePath) && isset($filePath['fileContent'])) {
             // File from memory
@@ -316,7 +315,7 @@ class RestClient
     }
 
     /**
-     * @param $uri
+     * @param string $uri
      *
      * @return string
      */
diff --git a/src/Mailgun/Messages/BatchMessage.php b/src/Mailgun/Messages/BatchMessage.php
index 162d709..2df95c3 100644
--- a/src/Mailgun/Messages/BatchMessage.php
+++ b/src/Mailgun/Messages/BatchMessage.php
@@ -78,7 +78,7 @@ class BatchMessage extends MessageBuilder
     {
         if (array_key_exists($headerName, $this->counters['recipients'])) {
             if ($this->counters['recipients'][$headerName] == Api::RECIPIENT_COUNT_LIMIT) {
-                if ($this->autoSend == false) {
+                if (false === $this->autoSend) {
                     throw new TooManyParameters(ExceptionMessages::TOO_MANY_RECIPIENTS);
                 }
                 $this->sendMessage();
diff --git a/src/Mailgun/Messages/MessageBuilder.php b/src/Mailgun/Messages/MessageBuilder.php
index 0aea16a..34dd4da 100644
--- a/src/Mailgun/Messages/MessageBuilder.php
+++ b/src/Mailgun/Messages/MessageBuilder.php
@@ -142,6 +142,9 @@ class MessageBuilder
         if ($this->counters['recipients']['to'] > Api::RECIPIENT_COUNT_LIMIT) {
             throw new TooManyParameters(ExceptionMessages::TOO_MANY_PARAMETERS_RECIPIENT);
         }
+
+        $variables = is_array($variables) ? $variables : [];
+
         $this->addRecipient('to', $address, $variables);
 
         return end($this->message['to']);
@@ -160,6 +163,9 @@ class MessageBuilder
         if ($this->counters['recipients']['cc'] > Api::RECIPIENT_COUNT_LIMIT) {
             throw new TooManyParameters(ExceptionMessages::TOO_MANY_PARAMETERS_RECIPIENT);
         }
+
+        $variables = is_array($variables) ? $variables : [];
+
         $this->addRecipient('cc', $address, $variables);
 
         return end($this->message['cc']);
@@ -178,6 +184,9 @@ class MessageBuilder
         if ($this->counters['recipients']['bcc'] > Api::RECIPIENT_COUNT_LIMIT) {
             throw new TooManyParameters(ExceptionMessages::TOO_MANY_PARAMETERS_RECIPIENT);
         }
+
+        $variables = is_array($variables) ? $variables : [];
+
         $this->addRecipient('bcc', $address, $variables);
 
         return end($this->message['bcc']);
@@ -191,6 +200,8 @@ class MessageBuilder
      */
     public function setFromAddress($address, $variables = null)
     {
+        $variables = is_array($variables) ? $variables : [];
+
         $this->addRecipient('from', $address, $variables);
 
         return $this->message['from'];
@@ -204,6 +215,8 @@ class MessageBuilder
      */
     public function setReplyToAddress($address, $variables = null)
     {
+        $variables = is_array($variables) ? $variables : [];
+
         $this->addRecipient('h:reply-to', $address, $variables);
 
         return $this->message['h:reply-to'];
diff --git a/src/Mailgun/Resource/Api/Domain/CreateResponse.php b/src/Mailgun/Resource/Api/Domain/CreateResponse.php
index 3145277..1df480a 100644
--- a/src/Mailgun/Resource/Api/Domain/CreateResponse.php
+++ b/src/Mailgun/Resource/Api/Domain/CreateResponse.php
@@ -82,6 +82,7 @@ final class CreateResponse implements ApiResponse
         $this->domain = $domainInfo;
         $this->inboundDnsRecords = $rxRecords;
         $this->outboundDnsRecords = $txRecords;
+        $this->message = $message;
     }
 
     /**
diff --git a/src/Mailgun/Resource/Api/Domain/Domain.php b/src/Mailgun/Resource/Api/Domain/Domain.php
index 06015c7..d696e75 100644
--- a/src/Mailgun/Resource/Api/Domain/Domain.php
+++ b/src/Mailgun/Resource/Api/Domain/Domain.php
@@ -72,7 +72,7 @@ final class Domain
     /**
      * @param string    $name
      * @param string    $smtpLogin
-     * @param string    $smtpPass
+     * @param string    $smtpPassword
      * @param bool      $wildcard
      * @param string    $spamAction
      * @param string    $state
diff --git a/src/Mailgun/Resource/Api/Message/ShowResponse.php b/src/Mailgun/Resource/Api/Message/ShowResponse.php
index 47847bd..0ce4a5e 100644
--- a/src/Mailgun/Resource/Api/Message/ShowResponse.php
+++ b/src/Mailgun/Resource/Api/Message/ShowResponse.php
@@ -338,14 +338,6 @@ class ShowResponse implements ApiResponse
         return $this->attachments;
     }
 
-    /**
-     * @param array $attachments
-     */
-    private function setAttachments(array $attachments)
-    {
-        $this->attachments = $attachments;
-    }
-
     /**
      * @return string
      */
@@ -370,14 +362,6 @@ class ShowResponse implements ApiResponse
         return $this->contentIdMap;
     }
 
-    /**
-     * @param string $contentIdMap
-     */
-    private function setContentIdMap($contentIdMap)
-    {
-        $this->contentIdMap = $contentIdMap;
-    }
-
     /**
      * @return array
      */
diff --git a/src/Mailgun/Resource/Api/Stats/AllResponseItem.php b/src/Mailgun/Resource/Api/Stats/AllResponseItem.php
index 086a72b..8233f4c 100644
--- a/src/Mailgun/Resource/Api/Stats/AllResponseItem.php
+++ b/src/Mailgun/Resource/Api/Stats/AllResponseItem.php
@@ -96,7 +96,7 @@ final class AllResponseItem
     }
 
     /**
-     * @return \string[]
+     * @return string[]
      */
     public function getTags()
     {