diff --git a/src/Paginator/CursorPaginator.php b/src/Paginator/CursorPaginator.php
index 7a87553..9bcb816 100644
--- a/src/Paginator/CursorPaginator.php
+++ b/src/Paginator/CursorPaginator.php
@@ -3,6 +3,8 @@
 
 namespace Zfegg\ApiSerializerExt\Paginator;
 
+use Traversable;
+
 class CursorPaginator implements CursorPaginatorInterface
 {
     use CursorPropertyTrait;
@@ -23,7 +25,7 @@ public function __construct(
         $this->itemsPerPage = $itemsPerPage;
     }
 
-    public function getIterator()
+    public function getIterator(): Traversable
     {
         foreach ($this->data as $item) {
             yield $item;
diff --git a/src/Paginator/Paginator.php b/src/Paginator/Paginator.php
index 0dfaa21..73f9846 100644
--- a/src/Paginator/Paginator.php
+++ b/src/Paginator/Paginator.php
@@ -22,12 +22,12 @@ public function __construct(iterable $data, int $count, int $currentPage = 1, in
         $this->itemsPerPage = $itemsPerPage;
     }
 
-    public function getIterator()
+    public function getIterator(): Traversable
     {
         return new \ArrayIterator($this->data);
     }
 
-    public function count()
+    public function count(): int
     {
         return $this->count;
     }