diff --git a/code-ch08/tx.py b/code-ch08/tx.py
index 500bea16..26d76b17 100644
--- a/code-ch08/tx.py
+++ b/code-ch08/tx.py
@@ -29,7 +29,7 @@ def get_url(cls, testnet=False):
     @classmethod
     def fetch(cls, tx_id, testnet=False, fresh=False):
         if fresh or (tx_id not in cls.cache):
-            url = '{}/tx/{}.hex'.format(cls.get_url(testnet), tx_id)
+            url = '{}/tx/{}/hex'.format(cls.get_url(testnet), tx_id)
             response = requests.get(url)
             try:
                 raw = bytes.fromhex(response.text.strip())