diff --git a/src/Ray.php b/src/Ray.php
index 33310fe..b673f5d 100644
--- a/src/Ray.php
+++ b/src/Ray.php
@@ -859,7 +859,7 @@ protected function notifyWhenRateLimitReached(): void
         self::rateLimiter()->notify();
     }
 
-    public static function beforeSendRequest(Closure $closure): void
+    public static function beforeSendRequest(null|Closure $closure): void
     {
         static::$beforeSendRequest = $closure;
     }