diff --git a/foxyproxy/00-foxyproxy.yml b/foxyproxy/00-foxyproxy.yml
index c4586ff3..524ba23e 100644
--- a/foxyproxy/00-foxyproxy.yml
+++ b/foxyproxy/00-foxyproxy.yml
@@ -10,5 +10,7 @@ proxies:
     description: Title or Description
     mandatory: false
 
-  color:  # Color
+  color:
+    description: Color
+    regexp: ^#(?:[0-9a-f]{3}){1,2}$
 ...