diff --git a/README.md b/README.md
index e772fde..216f2e4 100644
--- a/README.md
+++ b/README.md
@@ -91,3 +91,14 @@ docker build .
 ```
 
 That's it. The `Dockerfile` and bash scripts handle all the downloading, building, and packing. You can also add tags, push to your favorite docker registry, or use `buildx` to build multi architecture images.
+
+## Environment variables
+Environment variables can be set in the docker-compose.yaml file or in the command line using `-e $variable_name=true`.
+```
+docker run -d --name=protonmail-bridge -v protonmail:/root -e cache_enabled=true shenxn/protonmail-bridge
+```
+
+**variable**|**description**|**default**
+-- | -- | --
+cache_enabled|Controls if the mail cache is enabled in the prefs.json file.|false
+