diff --git a/pygti/auth.py b/pygti/auth.py
index 5d733fc..9a96b2f 100644
--- a/pygti/auth.py
+++ b/pygti/auth.py
@@ -39,7 +39,7 @@ async def request(
 
         payload.update({"version": 38})
 
-        data = json.dumps(payload).encode("UTF-8")
+        data = self.websession.json_serialize(payload).encode("UTF-8")
 
         signature = base64.b64encode(
             hmac.new(self.password.encode("UTF-8"), data, hashlib.sha1).digest()