diff --git a/backend/requirements.txt b/backend/requirements.txt
index b4d58d7..f156d6d 100644
--- a/backend/requirements.txt
+++ b/backend/requirements.txt
@@ -1,5 +1,6 @@
 fastapi==0.109.0
 uvicorn[standard]==0.23.2
-httpx==0.28.1
+# Allow any 0.28.x httpx compatible with Python 3.12; exact 0.28.4 may not be available
+httpx>=0.28.0,<0.29.0
 python-jose[cryptography]==3.3.0
 pydantic==2.8.0