diff --git a/internal/base64.go b/internal/base64.go
index 1cdd891..c12bfba 100644
--- a/internal/base64.go
+++ b/internal/base64.go
@@ -7,6 +7,11 @@ import (
 
 func DecodeBase64(s string) (string, error) {
 	s = strings.TrimSpace(s)
+	// url safe
+	if strings.Contains(s, "-") || strings.Contains(s, "_") {
+		s = strings.Replace(s, "-", "+", -1)
+		s = strings.Replace(s, "_", "/", -1)
+	}
 	if len(s)%4 != 0 {
 		s += strings.Repeat("=", 4-len(s)%4)
 	}