diff --git a/web/lib/mastodon-postLength.php b/web/lib/mastodon-postLength.php
new file mode 100644
index 0000000..0202ce9
--- /dev/null
+++ b/web/lib/mastodon-postLength.php
@@ -0,0 +1,16 @@
+<?php
+
+function postLength($post,&$tldsregex) {
+//	echo "-A-> |{$post}|\n";
+	// for some reason, mastodon seems to check tld existence only on http(s) links - see next regexp
+	$res=preg_replace('#(^|\W)(@[a-zA-Z0-9_]+)@(([a-z0-9]([a-z0-9-]+[a-z0-9])?){1,63}\.)+([a-z0-9]([a-z0-9-]+[a-z0-9])?){1,63}\b#u', '$1$2', $post);
+	if (!is_null($res)) $post=$res;
+//	$res=preg_replace('#(^|\W)https?://(([a-z0-9]([a-z0-9-]+[a-z0-9])?){1,63}\.)+([a-z0-9]([a-z0-9-]+[a-z0-9])?){1,63}(/\S*[\w=?_-])?#u', '$1HTTP://UUUUUUUUUUUUUUUU', $post);
+	// on http(s) links mastodon checks if tld exists...
+	$res=preg_replace('#(^|\W)https?://(([a-z0-9]([a-z0-9-]+[a-z0-9])?){1,63}\.)+('.$tldsregex.')(/\S*[\w/=_\-])?#u', '$1UUUUUUUUUUUUUUUUUUUUUUU', $post);
+	if (!is_null($res)) $post=$res;
+//	echo "-B-> |{$post}|\n";
+	return mb_strlen($post,'UTF-8');
+}
+
+?>