diff --git a/README.md b/README.md
index 1d121b0..3d1239f 100644
--- a/README.md
+++ b/README.md
@@ -53,6 +53,7 @@ Remove `args` to send the default message.
 * video - optional. video message
 * debug - optional. enable debug mode
 * format - optional. `markdown` or `html`
+* message - optional. custom message
 * message_file - optional. overwrite the default message template with the contents of the specified file.
 
 ## Example