diff --git a/main.go b/main.go
index 89244fa..3c290cb 100644
--- a/main.go
+++ b/main.go
@@ -41,7 +41,7 @@ import (
 // ──────────────────────────────────────────────────────────────────────────────
 // Config
 // ──────────────────────────────────────────────────────────────────────────────
-const defaultDelay = 5 * time.Second // default gap between two downloads
+const defaultDelay = 2 * time.Second // default gap between two downloads
 
 var defaultLists = map[string]string{
 	"bitwire":                                      "https://raw.githubusercontent.com/bitwire-it/ipblocklist/refs/heads/main/ip-list.txt",
@@ -603,6 +603,7 @@ func main() {
 	outDir := flag.String("out", "./lists/", "target directory")
 	listFile := flag.String("list", "", "optional text file with URLs or Name|URL pairs (overrides built-in map)")
 	listenAddr := flag.String("listen", ":8080", "HTTP listen address (e.g. :8080 or 127.0.0.1:8000)")
+	listenPrefix := flag.String("prefix", "http://importer:8080", "HTTP prefix for url in /lists.json")
 	flag.Parse()
 
 	if *serveonly != "1" {
@@ -654,7 +655,15 @@ func main() {
 		w.Header().Set("Content-Type", "application/json; charset=utf-8")
 		enc := json.NewEncoder(w)
 		enc.SetIndent("", "  ")
-		if err := enc.Encode(defaultLists); err != nil {
+		data, err := buildIndexData(*outDir)
+		if err != nil {
+			fmt.Println("Error Build-Index")
+		}
+		d := map[string]string{}
+		for _, b := range data.Files {
+			d[b.Name] = *listenPrefix + "/lists/" + b.Name
+		}
+		if err := enc.Encode(d); err != nil {
 			http.Error(w, err.Error(), http.StatusInternalServerError)
 		}
 	})