diff --git a/src/callosum/lower/redis_common.py b/src/callosum/lower/redis_common.py
new file mode 100644
index 0000000..bbe5c39
--- /dev/null
+++ b/src/callosum/lower/redis_common.py
@@ -0,0 +1,12 @@
+def redis_addr_to_url(
+    value: str | tuple[str, int],
+    *,
+    scheme: str = "redis",
+) -> str:
+    match value:
+        case str():
+            return f"{scheme}://{value}"
+        case (host, port):
+            return f"{scheme}://{host}:{port}"
+        case _:
+            raise ValueError("unrecognized address format", value)