diff --git a/readme.md b/readme.md
index 09264e9..372ac56 100644
--- a/readme.md
+++ b/readme.md
@@ -15,7 +15,9 @@
 
 ## installing & running
 
-`db-rest` expects a [Redis](https://redis.io/) server running on `127.0.0.1:6379` (default port), but you can set the `REDIS_URL` environment variable to change this.
+### access to Redis
+
+It is recommended that you let `bvg-rest` cache HAFAS responses within a [Redis](https://redis.io/) cache. To use this feature, set `$REDIS_URL` (e.g. to `redis://localhost:6379/1` when running Redis locally).
 
 ### via Docker