diff --git a/bp/product/routes.py b/bp/product/routes.py
index 9a51042..7eae4c6 100644
--- a/bp/product/routes.py
+++ b/bp/product/routes.py
@@ -159,7 +159,8 @@ def register():
 
     @bp.post("/cart/")
     @clear_cache(tag="browse", tag_scope="user")
-    async def cart(slug: str):
+    async def cart(**_kw):
+        slug = g.product_slug
         # make sure product exists (we *allow* deleted_at != None later if you want)
         product_id = await g.s.scalar(
             select(Product.id).where(