diff --git a/README.md b/README.md
index df39988..d4ad4bc 100644
--- a/README.md
+++ b/README.md
@@ -19,6 +19,13 @@ The actual configuration happens in two or more files:
 
 Example:
 
+*.env*
+```text
+CF_API_TOKEN=0123456789abcdef0123456789abcdef01234
+CHECK_INTERVAL_SECONDS=30                   // Defaults to 60 if missing
+UPTIME_URL=https://example.org/uptime/id12  // Entirely optional
+```
+
 *interfaces.toml*
 ```toml
 host_address = "::edcb:a098:7654:3210"