diff --git a/php/src/mail/mailer.php b/php/src/mail/mailer.php
index d11eb34..ac2e9ad 100644
--- a/php/src/mail/mailer.php
+++ b/php/src/mail/mailer.php
@@ -6,38 +6,26 @@ use nulib\cl;
 use nulib\cv;
 use nulib\exceptions;
 use nulib\output\msg;
+use nulib\php\types\vbool;
 use nulib\str;
 use PHPMailer\PHPMailer\PHPMailer;
 use PHPMailer\PHPMailer\SMTP;
 
 class mailer {
   private static function is_bool(&$value): bool {
-    if ($value === null) {
-      return false;
-    } elseif (is_bool($value)) {
+    if ($value === null) return false;
+    elseif (is_bool($value)) return true;
+    elseif (is_numeric($value)) {
+      $value = $value != 0;
       return true;
-    } elseif (is_int($value)) {
-      $value = boolval($value);
+    } elseif (vbool::is_yes($value)) {
+      $value = true;
+      return true;
+    } elseif ($value === "" || vbool::is_no($value)) {
+      $value = false;
       return true;
-    } else {
-      switch (strval($value)) {
-      case "":
-      case "0":
-      case "no":
-      case "off":
-      case "false":
-        $value = false;
-        return true;
-      case "1":
-      case "yes":
-      case "on":
-      case "true":
-        $value = true;
-        return true;
-      default:
-        return false;
-      }
     }
+    return false;
   }
 
   private static function get_bool($value): bool {
@@ -120,19 +108,14 @@ class mailer {
     $mailer->SMTPDebug = $debug;
     # auth, username, password
     $username = $params["username"] ?? null;
-    $username ??= cv::vn(getenv("NULIB_MAIL_USERNAME"));
     $password = $params["password"] ?? null;
-    $password ??= cv::vn(getenv("NULIB_MAIL_PASSWORD"));
     $auth = $params["auth"] ?? null;
-    $auth ??= cv::vn(getenv("NULIB_MAIL_AUTH"));
     $auth ??= $username !== null && $password !== null;
     $mailer->SMTPAuth = self::get_bool($auth);
     $mailer->Username = $username;
     $mailer->Password = $password;
     # secure
-    $secure = $params["secure"] ?? null;
-    $secure ??= cv::vn(getenv("NULIB_MAIL_SECURE"));
-    $secure ??= false;
+    $secure = $params["secure"] ?? false;
     if (self::is_bool($secure)) {
       if (!$secure) {
         $mailer->SMTPSecure = "";