diff --git a/php/src/mail/mailer.php b/php/src/mail/mailer.php
index f9510dc..3f92202 100644
--- a/php/src/mail/mailer.php
+++ b/php/src/mail/mailer.php
@@ -1,6 +1,7 @@
 <?php
 namespace nulib\mail;
 
+use nulib\app\config;
 use nulib\cl;
 use nulib\cv;
 use nulib\output\msg;
@@ -56,23 +57,38 @@ class mailer {
     "secure" => "?string",
   ];
 
+  static function resolve_params(?array $params=null): array {
+    $envParams = [
+      "backend" => cv::vn(getenv("NULIB_MAIL_BACKEND")),
+      "debug" => cv::vn(getenv("NULIB_MAIL_DEBUG")),
+      "host" => cv::vn(getenv("NULIB_MAIL_HOST")),
+      "port" => cv::vn(getenv("NULIB_MAIL_PORT")),
+      "auth" => cv::vn(getenv("NULIB_MAIL_AUTH")),
+      "username" => cv::vn(getenv("NULIB_MAIL_USERNAME")),
+      "password" => cv::vn(getenv("NULIB_MAIL_PASSWORD")),
+      "secure" => cv::vn(getenv("NULIB_MAIL_SECURE")),
+    ];
+    $configParams = config::k("mailer");
+    foreach (array_keys(self::SCHEMA) as $key) {
+      $params[$key] ??= $envParams[$key] ?? null;
+      $params[$key] ??= $configParams[$key] ?? null;
+    }
+    return $params;
+  }
+
   static function get(?array $params=null, ?bool $exceptions=null): PHPMailer {
+    $params = self::resolve_params($params);
+
     $mailer = new PHPMailer($exceptions);
     $mailer->setLanguage("fr");
     $mailer->CharSet = PHPMailer::CHARSET_UTF8;
     # backend
-    $backend = $params["backend"] ?? null;
-    $backend ??= cv::vn(getenv("NULIB_MAIL_BACKEND"));
-    $backend ??= "smtp";
+    $backend = $params["backend"] ?? "smtp";
     switch ($backend) {
     case "smtp":
-      # host
+      # host, port
       $host = $params["host"] ?? null;
-      $host ??= cv::vn(getenv("NULIB_MAIL_HOST"));
-      # port
-      $port = $params["port"] ?? null;
-      $port ??= cv::vn(getenv("NULIB_MAIL_PORT"));
-      $port ??= 25;
+      $port = $params["port"] ?? 25;
       if ($host === null) {
         throw new ValueException("mail host is required");
       }
@@ -93,9 +109,7 @@ class mailer {
       throw ValueException::invalid_value($backend, "mailer backend");
     }
     # debug
-    $debug = $params["debug"] ?? null;
-    $debug ??= cv::vn(getenv("NULIB_MAIL_DEBUG"));
-    $debug ??= SMTP::DEBUG_OFF;
+    $debug = $params["debug"] ?? SMTP::DEBUG_OFF;
     if (is_int($debug)) {
       if ($debug < SMTP::DEBUG_OFF) $debug = SMTP::DEBUG_OFF;
       elseif ($debug > SMTP::DEBUG_LOWLEVEL) $debug = SMTP::DEBUG_LOWLEVEL;
diff --git a/php/tbin/mailer-devel.yml b/php/tbin/mailer-devel.yml
new file mode 100644
index 0000000..1190d9f
--- /dev/null
+++ b/php/tbin/mailer-devel.yml
@@ -0,0 +1,5 @@
+# -*- coding: utf-8 mode: yaml -*- vim:sw=2:sts=2:et:ai:si:sta:fenc=utf-8
+
+app:
+  mailer:
+    host: maildev.devel.self
diff --git a/php/tbin/mailer-test.yml b/php/tbin/mailer-test.yml
new file mode 100644
index 0000000..6a3f17e
--- /dev/null
+++ b/php/tbin/mailer-test.yml
@@ -0,0 +1,7 @@
+# -*- coding: utf-8 mode: yaml -*- vim:sw=2:sts=2:et:ai:si:sta:fenc=utf-8
+
+app:
+  mailer:
+    host: maildev.univ-reunion.fr
+    username: mel
+    password: gibson