diff --git a/lib/constants.js b/lib/constants.js
index 1cf874a..9567b91 100644
--- a/lib/constants.js
+++ b/lib/constants.js
@@ -33,11 +33,12 @@ export const LIST_TYPE = {
 };
 
 export const USER_DEFINED_ALLOWLIST_URLS = process.env.ALLOWLIST_URLS
-  ? process.env.ALLOWLIST_URLS.split("\n")
+  // .filter(x => x) removes empty items from the URL arrays
+  ? process.env.ALLOWLIST_URLS.split("\n").filter(x => x)
   : undefined;
 
 export const USER_DEFINED_BLOCKLIST_URLS = process.env.BLOCKLIST_URLS
-  ? process.env.BLOCKLIST_URLS.split("\n")
+  ? process.env.BLOCKLIST_URLS.split("\n").filter(x => x)
   : undefined;
 
 export const RECOMMENDED_ALLOWLIST_URLS = [