diff --git a/rollbar/lib/_async.py b/rollbar/lib/_async.py
index 1b025258..4c233069 100644
--- a/rollbar/lib/_async.py
+++ b/rollbar/lib/_async.py
@@ -139,7 +139,7 @@ async def _post_api_httpx(path, payload_str, access_token=None):
     ) as client:
         resp = await client.post(
             url,
-            data=payload_str,
+            content=payload_str,
             headers=headers,
             timeout=rollbar.SETTINGS.get('timeout', DEFAULT_TIMEOUT),
         )