diff --git a/api.php b/api.php
index 37acf5f..af6285a 100644
--- a/api.php
+++ b/api.php
@@ -2962,6 +2962,28 @@ switch ($action) {
         echo json_encode($mbs);
         break;
 
+    case 'mailbox_debug':
+        requireAdmin();
+        $companyId = requireCompany();
+        $mailboxes = dbLoadMailboxes($companyId);
+        $debug = array_map(function($mb) {
+            return [
+                'id' => $mb['id'],
+                'nimi' => $mb['nimi'],
+                'imap_host' => $mb['imap_host'] ?? '',
+                'imap_user' => $mb['imap_user'] ?? '',
+                'imap_pass_len' => strlen($mb['imap_password'] ?? ''),
+                'smtp_host' => $mb['smtp_host'] ?? '',
+                'smtp_port' => $mb['smtp_port'] ?? '',
+                'smtp_user' => $mb['smtp_user'] ?? '',
+                'smtp_pass_len' => strlen($mb['smtp_password'] ?? ''),
+                'smtp_encryption' => $mb['smtp_encryption'] ?? '',
+                'smtp_from_email' => $mb['smtp_from_email'] ?? '',
+            ];
+        }, $mailboxes);
+        echo json_encode($debug, JSON_PRETTY_PRINT);
+        break;
+
     case 'mailbox_save':
         requireAdmin();
         $companyId = requireCompany();