diff --git a/src/Api.php b/src/Api.php
index 629802a..02c427f 100644
--- a/src/Api.php
+++ b/src/Api.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Tarantool\Mapper;
 
 use Tarantool\Client\Schema\Criteria;
diff --git a/src/Change.php b/src/Change.php
index 936e142..4f05c86 100644
--- a/src/Change.php
+++ b/src/Change.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Tarantool\Mapper;
 
 class Change