diff --git a/src/JsonRequestTransformerListener.php b/src/JsonRequestTransformerListener.php
index 0938ec5..ba61360 100755
--- a/src/JsonRequestTransformerListener.php
+++ b/src/JsonRequestTransformerListener.php
@@ -51,7 +51,15 @@ private function transformJsonBody(Request $request): bool
     {
         $data = json_decode((string) $request->getContent(), true);
 
-        if (JSON_ERROR_NONE !== json_last_error() || !is_array($data)) {
+        if (JSON_ERROR_NONE !== json_last_error()) {
+            return false;
+        }
+
+        if (is_null($data) || is_bool($data)) {
+            return true;
+        }
+
+        if (!is_array($data)) {
             return false;
         }
 
diff --git a/test/JsonRequestTransformerListenerTest.php b/test/JsonRequestTransformerListenerTest.php
index 83d2125..d09044d 100755
--- a/test/JsonRequestTransformerListenerTest.php
+++ b/test/JsonRequestTransformerListenerTest.php
@@ -104,6 +104,28 @@ public function notJsonContentTypes()
         ];
     }
 
+    /**
+     * @test
+     * @dataProvider provideValidNonStructuredJson
+     */
+    public function it_also_accepts_valid_json_if_its_not_structured_content($body): void
+    {
+        $request = $this->createRequest('application/json', $body);
+        $event = $this->createGetResponseEventMock($request);
+
+        $this->listener->onKernelRequest($event);
+        $this->assertNull($event->getResponse());
+    }
+
+    public static function provideValidNonStructuredJson()
+    {
+        return [
+            'boolean true' => ['true'],
+            'boolean false' => ['false'],
+            'null' => ['null'],
+        ];
+    }
+
     private function createRequest($contentType, $body)
     {
         $request = new Request([], [], [], [], [], [], $body);