diff --git a/docs/content/dns/_index.md b/docs/content/dns/_index.md
index 7078e411..d075229c 100644
--- a/docs/content/dns/_index.md
+++ b/docs/content/dns/_index.md
@@ -41,7 +41,7 @@ $ cat /the/path/to/my/email
 foo@bar.com
 
 $ CLOUDFLARE_EMAIL_FILE=/the/path/to/my/email \
-CLOUDFLARE_API_KEY=/the/path/to/my/key \
+CLOUDFLARE_API_KEY_FILE=/the/path/to/my/key \
 lego --dns cloudflare --domains www.example.com --email me@bar.com run
 ```