diff --git a/backend/src/api/nft_manager.py b/backend/src/api/nft_manager.py
index d1a087a..707cb9a 100644
--- a/backend/src/api/nft_manager.py
+++ b/backend/src/api/nft_manager.py
@@ -102,7 +102,7 @@ class NftManager:
         Return parsed JSON (a Python dict/list) for `nft -j list ruleset`.
         Handle possible double-encoded outputs by unwrapping.
         """
-        rc, out, err = self.json_cmd("list ruleset")
+        rc, out, err = self.cmd("list ruleset -j")
         if rc != 0:
             raise NftError(f"nft list ruleset failed (json): {err}")
         try: