diff --git a/swh/core/api/__init__.py b/swh/core/api/__init__.py
--- a/swh/core/api/__init__.py
+++ b/swh/core/api/__init__.py
@@ -179,7 +179,7 @@
             post_data.pop("db", None)
 
             # Send the request.
-            return self.post(meth._endpoint_path, post_data)
+            return self._post(meth._endpoint_path, post_data)
 
         if meth_name not in attributes:
             attributes[meth_name] = meth_
diff --git a/swh/core/api/tests/test_rpc_client.py b/swh/core/api/tests/test_rpc_client.py
--- a/swh/core/api/tests/test_rpc_client.py
+++ b/swh/core/api/tests/test_rpc_client.py
@@ -104,7 +104,7 @@
     )
 
     with pytest.raises(APIError) as exc_info:
-        rpc_client.post("connection_error", data={})
+        rpc_client._post("connection_error", data={})
 
     assert type(exc_info.value.args[0]) == ConnectionError
     assert str(exc_info.value.args[0]) == error_message
@@ -142,7 +142,7 @@
     )
 
     with pytest.raises(ReraiseException) as exc_info:
-        rpc_client.post(endpoint, data={})
+        rpc_client._post(endpoint, data={})
 
     assert str(exc_info.value) == error_message
 
@@ -171,7 +171,7 @@
     )
 
     with pytest.raises(RemoteException) as exc_info:
-        rpc_client.post(endpoint, data={})
+        rpc_client._post(endpoint, data={})
 
     assert str(exc_info.value.args[0]["type"]) == "Exception"
     assert str(exc_info.value.args[0]["message"]) == error_message