diff --git a/backend/src/api/nft_manager.py b/backend/src/api/nft_manager.py
index d5f4045..e8ebe13 100644
--- a/backend/src/api/nft_manager.py
+++ b/backend/src/api/nft_manager.py
@@ -714,7 +714,7 @@ def list_rules():
         except Exception as e:
             logger.debug("list_rules: populate_text_from_chain_text failed: %s", e)
 
-        ruleset_model = RulesetModel.parse_obj(custom)
+        ruleset_model = json.dumps(RulesetModel.parse_obj(custom))
         return RulesetOut(ruleset=ruleset_model)
     except NftError as e:
         logger.exception("list_rules failed")