diff --git a/DependencyInjection/Configuration.php b/DependencyInjection/Configuration.php
index ac675ef3c..ac468b87f 100644
--- a/DependencyInjection/Configuration.php
+++ b/DependencyInjection/Configuration.php
@@ -13,6 +13,7 @@
 
 use GraphQL\Validator\Rules\QueryComplexity;
 use GraphQL\Validator\Rules\QueryDepth;
+use Overblog\GraphQLBundle\Error\ErrorHandler;
 use Symfony\Component\Config\Definition\Builder\TreeBuilder;
 use Symfony\Component\Config\Definition\ConfigurationInterface;
 
@@ -83,6 +84,7 @@ public function getConfigTreeBuilder()
                             ->end()
                         ->end()
                         ->arrayNode('exceptions')
+                            ->addDefaultsIfNotSet()
                             ->children()
                                 ->arrayNode('warnings')
                                     ->treatNullLike([])
@@ -96,10 +98,10 @@ public function getConfigTreeBuilder()
                                     ->addDefaultsIfNotSet()
                                     ->children()
                                         ->scalarNode('warnings')
-                                            ->defaultValue('Overblog\\GraphQLBundle\\Error\\UserWarning')
+                                            ->defaultValue(ErrorHandler::DEFAULT_USER_WARNING_CLASS)
                                         ->end()
                                         ->scalarNode('errors')
-                                            ->defaultValue('Overblog\\GraphQLBundle\\Error\\UserError')
+                                            ->defaultValue(ErrorHandler::DEFAULT_USER_ERROR_CLASS)
                                         ->end()
                                     ->end()
                                 ->end()
diff --git a/DependencyInjection/OverblogGraphQLExtension.php b/DependencyInjection/OverblogGraphQLExtension.php
index 5644c2928..e0fdc2ce6 100644
--- a/DependencyInjection/OverblogGraphQLExtension.php
+++ b/DependencyInjection/OverblogGraphQLExtension.php
@@ -99,17 +99,17 @@ private function setGraphiQLTemplate(array $config, ContainerBuilder $container)
 
     private function setErrorHandlerArguments(array $config, ContainerBuilder $container)
     {
+        $errorHandlerDefinition = $container->getDefinition($this->getAlias().'.error_handler');
+
         if (isset($config['definitions']['internal_error_message'])) {
-            $container
-                ->getDefinition($this->getAlias().'.error_handler')
-                ->replaceArgument(0, $config['definitions']['internal_error_message'])
-            ;
+            $errorHandlerDefinition->replaceArgument(0, $config['definitions']['internal_error_message']);
         }
 
         if (isset($config['definitions']['exceptions'])) {
-            $container
-                ->getDefinition($this->getAlias().'.error_handler')
+            $errorHandlerDefinition
                 ->replaceArgument(2, $this->buildExceptionMap($config['definitions']['exceptions']))
+                ->addMethodCall('setUserWarningClass', [$config['definitions']['exceptions']['types']['warnings']])
+                ->addMethodCall('setUserErrorClass', [$config['definitions']['exceptions']['types']['errors']])
             ;
         }
     }
diff --git a/Error/ErrorHandler.php b/Error/ErrorHandler.php
index fb610da23..4dd178ed5 100644
--- a/Error/ErrorHandler.php
+++ b/Error/ErrorHandler.php
@@ -15,10 +15,13 @@
 use GraphQL\Executor\ExecutionResult;
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
+use Psr\Log\LogLevel;
 
 class ErrorHandler
 {
     const DEFAULT_ERROR_MESSAGE = 'Internal server Error';
+    const DEFAULT_USER_WARNING_CLASS = 'Overblog\\GraphQLBundle\\Error\\UserWarning';
+    const DEFAULT_USER_ERROR_CLASS = 'Overblog\\GraphQLBundle\\Error\\UserError';
 
     /** @var LoggerInterface */
     private $logger;
@@ -29,6 +32,12 @@ class ErrorHandler
     /** @var array */
     private $exceptionMap;
 
+    /** @var string */
+    private $userWarningClass = self::DEFAULT_USER_WARNING_CLASS;
+
+    /** @var string */
+    private $userErrorClass = self::DEFAULT_USER_ERROR_CLASS;
+
     public function __construct($internalErrorMessage = null, LoggerInterface $logger = null, array $exceptionMap = [])
     {
         $this->logger = (null === $logger) ? new NullLogger() : $logger;
@@ -39,6 +48,20 @@ public function __construct($internalErrorMessage = null, LoggerInterface $logge
         $this->exceptionMap = $exceptionMap;
     }
 
+    public function setUserWarningClass($userWarningClass)
+    {
+        $this->userWarningClass = $userWarningClass;
+
+        return $this;
+    }
+
+    public function setUserErrorClass($userErrorClass)
+    {
+        $this->userErrorClass = $userErrorClass;
+
+        return $this;
+    }
+
     /**
      * @param Error[] $errors
      * @param bool    $throwRawException
@@ -66,7 +89,8 @@ protected function treatExceptions(array $errors, $throwRawException)
                 continue;
             }
 
-            if ($rawException instanceof UserError) {
+            // user error
+            if ($rawException instanceof $this->userErrorClass) {
                 $treatedExceptions['errors'][] = $error;
                 if ($rawException->getPrevious()) {
                     $this->logException($rawException->getPrevious());
@@ -74,11 +98,11 @@ protected function treatExceptions(array $errors, $throwRawException)
                 continue;
             }
 
-            // user warnings
-            if ($rawException instanceof UserWarning) {
+            // user warning
+            if ($rawException instanceof $this->userWarningClass) {
                 $treatedExceptions['extensions']['warnings'][] = $error;
                 if ($rawException->getPrevious()) {
-                    $this->logException($rawException->getPrevious());
+                    $this->logException($rawException->getPrevious(), LogLevel::WARNING);
                 }
                 continue;
             }
@@ -97,7 +121,7 @@ protected function treatExceptions(array $errors, $throwRawException)
                 throw $rawException;
             }
 
-            $this->logException($rawException);
+            $this->logException($rawException, LogLevel::CRITICAL);
 
             $treatedExceptions['errors'][] = new Error(
                 $this->internalErrorMessage,
@@ -111,7 +135,7 @@ protected function treatExceptions(array $errors, $throwRawException)
         return $treatedExceptions;
     }
 
-    public function logException(\Exception $exception)
+    public function logException(\Exception $exception, $errorLevel = LogLevel::ERROR)
     {
         $message = sprintf(
             '%s: %s[%d] (caught exception) at %s line %s.',
@@ -122,7 +146,7 @@ public function logException(\Exception $exception)
             $exception->getLine()
         );
 
-        $this->logger->error($message, ['exception' => $exception]);
+        $this->logger->$errorLevel($message, ['exception' => $exception]);
     }
 
     public function handleErrors(ExecutionResult $executionResult, $throwRawException = false)