diff --git a/README.md b/README.md
index 8180ea1..b5601ab 100644
--- a/README.md
+++ b/README.md
@@ -8,6 +8,7 @@ Live demo on https://http2pic.haschek.at/
 ## Dependencies
 - [wkhtmltox](http://wkhtmltopdf.org/downloads.html)
 - "timeout" command
+- curl extension for PHP
 
 ## Install