diff --git a/Makefile b/Makefile
index cd662af..54997e7 100644
--- a/Makefile
+++ b/Makefile
@@ -40,4 +40,7 @@ distclean: clean
 	-rm -f be.bastelstu.chat.tar
 	-rm -f be.bastelstu.chat.tar.gz
 
+constants.php: option.xml
+	(echo "<?php" ; xq -r '.data.import.options.option[] | "define(\"" + (.["@name"] | ascii_upcase) + "\", " + .defaultvalue + ");"' < option.xml) > constants.php
+
 .PHONY: distclean clean
diff --git a/constants.php b/constants.php
new file mode 100644
index 0000000..1f830f0
--- /dev/null
+++ b/constants.php
@@ -0,0 +1,6 @@
+<?php
+define("CHAT_RELOADTIME", 3);
+define("CHAT_AUTOAWAYTIME", 0);
+define("CHAT_MAX_LENGTH", 500);
+define("CHAT_ARCHIVE_AFTER", 90);
+define("CHAT_LOG_ARCHIVETIME", 7);