diff --git a/src/matrix-api.c b/src/matrix-api.c
index 1e1d85a..244db7f 100644
--- a/src/matrix-api.c
+++ b/src/matrix-api.c
@@ -1435,7 +1435,7 @@ matrix_api_get_room_state(MatrixAPI *api,
  * @event_type: the type of state to look up
  * @state_key: (allow-none): the key of the state to look up. If
  *             @event_type is %NULL, this parameter is ignored
- * @content: the content of the state event
+ * @content: (transfer full): the content of the state event
  * @error: return location for a #GError, or %NULL
  *
  * Send a state event to the room. These events will be overwritten if
@@ -1453,7 +1453,7 @@ matrix_api_send_room_event(MatrixAPI *api,
                            const gchar *room_id,
                            const gchar *event_type,
                            const gchar *state_key,
-                           const JsonNode *content,
+                           JsonNode *content,
                            GError **error)
 {
     g_return_if_fail(MATRIX_IS_API(api));
diff --git a/src/matrix-api.h b/src/matrix-api.h
index 51f5012..1e16530 100644
--- a/src/matrix-api.h
+++ b/src/matrix-api.h
@@ -313,7 +313,7 @@ struct _MatrixAPIInterface {
                             const gchar *room_id,
                             const gchar *event_type,
                             const gchar *state_key,
-                            const JsonNode *content,
+                            JsonNode *content,
                             GError **error);
     void (*notify_room_typing)(MatrixAPI *api,
                                MatrixAPICallback callback,
@@ -730,7 +730,7 @@ void matrix_api_send_room_event(MatrixAPI *api,
                                 const gchar *room_id,
                                 const gchar *event_type,
                                 const gchar *state_key,
-                                const JsonNode *content,
+                                JsonNode *content,
                                 GError **error);
 void matrix_api_notify_room_typing(MatrixAPI *api,
                                    MatrixAPICallback callback,