diff --git a/src/Domain/Exception/AlertException.php b/src/Domain/Exception/AlertException.php
index 670c67b..2f5e955 100644
--- a/src/Domain/Exception/AlertException.php
+++ b/src/Domain/Exception/AlertException.php
@@ -11,7 +11,9 @@
  *
  * @category Exception
  */
-class AlertException extends Exception
+class AlertException extends Exception implements ExceptionLevelsInterface, ParentExceptionInterface
 {
-    use ParentExceptionTrait;
+    protected string $level = self::EXCEPTION_LEVEL_ALERT;
+
+    use ParentExceptionTrait, ExceptionLevelsTrait;
 }
diff --git a/src/Domain/Exception/CriticalException.php b/src/Domain/Exception/CriticalException.php
index 3a66f1f..6f311da 100644
--- a/src/Domain/Exception/CriticalException.php
+++ b/src/Domain/Exception/CriticalException.php
@@ -11,7 +11,9 @@
  *
  * @category Exception
  */
-class CriticalException extends Exception
+class CriticalException extends Exception implements ExceptionLevelsInterface, ParentExceptionInterface
 {
-    use ParentExceptionTrait;
+    protected string $level = self::EXCEPTION_LEVEL_CRITICAL;
+
+    use ParentExceptionTrait, ExceptionLevelsTrait;
 }
diff --git a/src/Domain/Exception/EmergencyException.php b/src/Domain/Exception/EmergencyException.php
index 0c17797..ae5c229 100644
--- a/src/Domain/Exception/EmergencyException.php
+++ b/src/Domain/Exception/EmergencyException.php
@@ -11,7 +11,9 @@
  *
  * @category Exception
  */
-class EmergencyException extends Exception
+class EmergencyException extends Exception implements ExceptionLevelsInterface, ParentExceptionInterface
 {
-    use ParentExceptionTrait;
+    protected string $level = self::EXCEPTION_LEVEL_EMERGENCY;
+
+    use ParentExceptionTrait, ExceptionLevelsTrait;
 }
diff --git a/src/Domain/Exception/ErrorException.php b/src/Domain/Exception/ErrorException.php
index 533d028..bb3b4f8 100644
--- a/src/Domain/Exception/ErrorException.php
+++ b/src/Domain/Exception/ErrorException.php
@@ -11,7 +11,7 @@
  *
  * @category Exception
  */
-class ErrorException extends Exception
+class ErrorException extends Exception implements ExceptionLevelsInterface, ParentExceptionInterface
 {
-    use ParentExceptionTrait;
+    use ParentExceptionTrait, ExceptionLevelsTrait;
 }
diff --git a/src/Domain/Exception/ExceptionLevelsInterface.php b/src/Domain/Exception/ExceptionLevelsInterface.php
new file mode 100644
index 0000000..ab425a7
--- /dev/null
+++ b/src/Domain/Exception/ExceptionLevelsInterface.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MicroModule\Base\Domain\Exception;
+
+use Throwable;
+
+/**
+ * Interface ExceptionLevelsInterface.
+ *
+ * @category Exception
+ */
+interface ExceptionLevelsInterface
+{
+    public const EXCEPTION_LEVEL_EMERGENCY  = 'emergency';
+    public const EXCEPTION_LEVEL_ALERT      = 'alert';
+    public const EXCEPTION_LEVEL_CRITICAL   = 'critical';
+    public const EXCEPTION_LEVEL_ERROR      = 'error';
+
+    /**
+     * Return exception level const.
+     */
+    public function getExceptionLevel(): string;
+}
diff --git a/src/Domain/Exception/ExceptionLevelsTrait.php b/src/Domain/Exception/ExceptionLevelsTrait.php
new file mode 100644
index 0000000..e9558f2
--- /dev/null
+++ b/src/Domain/Exception/ExceptionLevelsTrait.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MicroModule\Base\Domain\Exception;
+
+use Throwable;
+
+/**
+ * Trait ParentExceptionTrait.
+ *
+ * @category Exception
+ */
+trait ExceptionLevelsTrait
+{
+    /**
+     * Exception level.
+     */
+    protected string $levels = ExceptionLevelsInterface::EXCEPTION_LEVEL_ERROR;
+
+    /**
+     * Return exception level const.
+     */
+    public function getExceptionLevel(): string
+    {
+        return $this->levels;
+    }
+}
diff --git a/src/Domain/Exception/FactoryException.php b/src/Domain/Exception/FactoryException.php
index fd4e84f..a96c412 100644
--- a/src/Domain/Exception/FactoryException.php
+++ b/src/Domain/Exception/FactoryException.php
@@ -9,6 +9,6 @@
  *
  * @category Domain\Exception
  */
-final class FactoryException extends CriticalException
+class FactoryException extends CriticalException
 {
 }
diff --git a/src/Domain/Exception/InvalidDataException.php b/src/Domain/Exception/InvalidDataException.php
index e08d600..da58bdb 100644
--- a/src/Domain/Exception/InvalidDataException.php
+++ b/src/Domain/Exception/InvalidDataException.php
@@ -9,6 +9,6 @@
  *
  * @category Domain\Exception
  */
-final class InvalidDataException extends ErrorException
+class InvalidDataException extends ErrorException
 {
 }
diff --git a/src/Domain/Exception/InvalidDataTypeException.php b/src/Domain/Exception/InvalidDataTypeException.php
index ddbbdbc..ad01437 100644
--- a/src/Domain/Exception/InvalidDataTypeException.php
+++ b/src/Domain/Exception/InvalidDataTypeException.php
@@ -9,6 +9,6 @@
  *
  * @category Domain\Exception
  */
-final class InvalidDataTypeException extends ErrorException
+class InvalidDataTypeException extends ErrorException
 {
 }
diff --git a/src/Domain/Exception/InvalidResponseContentTypeException.php b/src/Domain/Exception/InvalidResponseContentTypeException.php
index 366704a..48b5487 100644
--- a/src/Domain/Exception/InvalidResponseContentTypeException.php
+++ b/src/Domain/Exception/InvalidResponseContentTypeException.php
@@ -9,6 +9,6 @@
  *
  * @category Domain\Exception
  */
-final class InvalidResponseContentTypeException extends CriticalException
+class InvalidResponseContentTypeException extends CriticalException
 {
 }
diff --git a/src/Domain/Exception/InvalidResponseStatusCodeException.php b/src/Domain/Exception/InvalidResponseStatusCodeException.php
index 44fa9e9..5122e56 100644
--- a/src/Domain/Exception/InvalidResponseStatusCodeException.php
+++ b/src/Domain/Exception/InvalidResponseStatusCodeException.php
@@ -9,6 +9,6 @@
  *
  * @category Domain\Exception
  */
-final class InvalidResponseStatusCodeException extends CriticalException
+class InvalidResponseStatusCodeException extends CriticalException
 {
 }
diff --git a/src/Domain/Exception/InvalidResponseStatusException.php b/src/Domain/Exception/InvalidResponseStatusException.php
index 49ec0b6..4207138 100644
--- a/src/Domain/Exception/InvalidResponseStatusException.php
+++ b/src/Domain/Exception/InvalidResponseStatusException.php
@@ -9,6 +9,6 @@
  *
  * @category Domain\Exception
  */
-final class InvalidResponseStatusException extends CriticalException
+class InvalidResponseStatusException extends CriticalException
 {
 }
diff --git a/src/Domain/Exception/LoggerException.php b/src/Domain/Exception/LoggerException.php
index 7872da2..0ebfe8b 100644
--- a/src/Domain/Exception/LoggerException.php
+++ b/src/Domain/Exception/LoggerException.php
@@ -9,6 +9,6 @@
  *
  * @category Domain\Exception
  */
-final class LoggerException extends ErrorException
+class LoggerException extends ErrorException
 {
 }