diff --git a/src/Documents/Document.php b/src/Documents/Document.php
index c2277f3..3dabaa9 100644
--- a/src/Documents/Document.php
+++ b/src/Documents/Document.php
@@ -30,7 +30,7 @@ public function id(): string
     /**
      * @return mixed
      */
-    public function content(string $key = null)
+    public function content(?string $key = null)
     {
         return Arr::get($this->content, $key);
     }
diff --git a/src/Documents/DocumentManager.php b/src/Documents/DocumentManager.php
index b9ef5eb..a08cfdc 100644
--- a/src/Documents/DocumentManager.php
+++ b/src/Documents/DocumentManager.php
@@ -27,7 +27,7 @@ public function index(
         string $indexName,
         Collection $documents,
         bool $refresh = false,
-        Routing $routing = null
+        ?Routing $routing = null
     ): self {
         $params = [
             'index' => $indexName,
@@ -62,7 +62,7 @@ public function delete(
         string $indexName,
         array $documentIds,
         bool $refresh = false,
-        Routing $routing = null
+        ?Routing $routing = null
     ): self {
         $params = [
             'index' => $indexName,
diff --git a/src/Indices/IndexBlueprint.php b/src/Indices/IndexBlueprint.php
index 0b831b1..38de3fc 100644
--- a/src/Indices/IndexBlueprint.php
+++ b/src/Indices/IndexBlueprint.php
@@ -17,7 +17,7 @@ final class IndexBlueprint
      */
     private $settings;
 
-    public function __construct(string $name, Mapping $mapping = null, Settings $settings = null)
+    public function __construct(string $name, ?Mapping $mapping = null, ?Settings $settings = null)
     {
         $this->name = $name;
         $this->mapping = $mapping;