diff --git a/composer.json b/composer.json
index dd4b52a..e76ed80 100644
--- a/composer.json
+++ b/composer.json
@@ -20,7 +20,7 @@
   },
   "require-dev": {
     "phpunit/phpunit": "~5.7|~6.0",
-    "squizlabs/php_codesniffer": "^2.3"
+    "squizlabs/php_codesniffer": "^3.5.8"
   },
   "autoload": {
     "psr-4": {
diff --git a/src/Service.php b/src/Service.php
index 94ce191..2094ddd 100644
--- a/src/Service.php
+++ b/src/Service.php
@@ -50,9 +50,13 @@ abstract class Service implements ServiceInterface
      */
     public function request(array $params, array $headers = [])
     {
-        $params['params'] = filter_params($params['params']);
+        if (!empty($params['params'])) {
+            $params['params'] = filter_params($params['params']);
+        }
 
-        /* Request API */
+        if (empty($params['params'])) {
+            $params['params'] = new \StdClass;
+        }
 
         $response = $this->getTransport()->request(new Request([
             'service' => $this->getName(),
diff --git a/src/Transport/Response.php b/src/Transport/Response.php
index c547031..ae15abf 100644
--- a/src/Transport/Response.php
+++ b/src/Transport/Response.php
@@ -7,7 +7,6 @@
 namespace Yandex\Direct\Transport;
 
 use Yandex\Direct\ConfigurableTrait;
-use Yandex\Direct\Exception\InvalidArgumentException;
 
 /**
  * Class TransportRequest