diff --git a/README.md b/README.md
index 30f503f..4e33a61 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,17 @@ Server for gemini protocol written in PHP
 ## Dependencies
 
 - PHP 7.x or higher
-- composer (getcomposer.org)
+- composer (see getcomposer.org for download/install instructions)
+
+For dev dependencies:
+- php-xml
+- php-mbstring
+
+You can install PHP + required dev extensions on debian-based linux with
+
+```
+sudo apt install php-cli php-xml php-mbstring
+```
 
 ## Installation