be sync

backend/url-shortener/DEPLOY.md

@@ -31,6 +31,8 @@ nginx -t && rc-service nginx reload
 nginx -t && rc-service nginx reload
 ```
 
+**Alpine/nginx note:** regex locations with `{n,m}` quantifiers must be **double-quoted** or nginx parses `{` as a block delimiter (`nginx: [emerg] improper regexp`).
+
 ## Verify
 
 ```bash

backend/url-shortener/deploy/nginx.be-url-shortener.fragment

@@ -16,8 +16,8 @@ server {
 		try_files $uri /index.php?$query_string;
 	}
 
-	# Short slug redirect (12–16 hex chars)
-	location ~ ^/[a-f0-9]{6,16}$ {
+	# Short slug redirect (6–16 hex chars). Regex MUST be quoted — bare {6,16} breaks nginx -t.
+	location ~ "^/[a-f0-9]{6,16}$" {
 		try_files $uri /index.php?$query_string;
 	}