diff --git a/CHANGELOG.md b/CHANGELOG.md
index be40c17..5dbb905 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/).
 - refactored code into multiple php files.
 - Requires PHP version  >=7.2
 - make all addresses lowercase  #30
+- fixed error when downloading email 
 
 ### Added 
 - better horizontal spacing for header (from @Spegeli) and style
@@ -24,6 +25,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/).
 - Blacklist some usernames, configurable  #27
 - copyToClipboard button #30
 - mail counter in title
+- rest api option
 
 ## [0.1.4] - 2017-04-15
 
diff --git a/src/pages.php b/src/controller.php
similarity index 70%
rename from src/pages.php
rename to src/controller.php
index f4a17f2..1bf3de0 100644
--- a/src/pages.php
+++ b/src/controller.php
@@ -1,8 +1,19 @@
 <?php
 
 require_once './imap_client.php';
+require_once './view.php';
 
-abstract class Page {
+
+abstract class Controller {
+
+    /**
+     * @var ViewHandler
+     */
+    protected $viewHandler;
+
+    public function setViewHandler(ViewHandler $outputHandler) {
+        $this->viewHandler = $outputHandler;
+    }
 
     function invoke(ImapClient $imapClient) {
     }
@@ -23,22 +34,12 @@ abstract class Page {
         $name = $word . $nr;
 
         $domain = $domains[array_rand($domains)];
-        header("location: ?$name@$domain");
-    }
-
-    /**
-     * print error and stop program.
-     * @param $status integer http status
-     * @param $text string error text
-     */
-    function error($status, $text) {
-        @http_response_code($status);
-        die("{\"error\": \"$text\"}");
+        $this->viewHandler->newAddress("$name@$domain");
     }
 
 }
 
-class RedirectToAddressPage extends Page {
+class RedirectToAddressController extends Controller {
     private $username;
     private $domain;
     private $config_blocked_usernames;
@@ -51,11 +52,11 @@ class RedirectToAddressPage extends Page {
 
     function invoke(ImapClient $imapClient) {
         $user = User::parseUsernameAndDomain($this->username, $this->domain, $this->config_blocked_usernames);
-        header("location: ?" . $user->username . "@" . $user->domain);
+        $this->viewHandler->newAddress($user->username . "@" . $user->domain);
     }
 }
 
-class DownloadEmailPage extends Page {
+class DownloadEmailController extends Controller {
 
     private $email_id;
     private $address;
@@ -75,21 +76,18 @@ class DownloadEmailPage extends Page {
         $this->if_invalid_redirect_to_random($user, $this->config_domains);
 
         $download_email_id = filter_var($this->email_id, FILTER_SANITIZE_NUMBER_INT);
-        if ($imapClient->load_one_email($download_email_id, $user) !== null) {
-            header("Content-Type: message/rfc822; charset=utf-8");
-            header("Content-Disposition: attachment; filename=\"" . $user->address . "-" . $download_email_id . ".eml\"");
-
-            $headers = imap_fetchheader($this->mailbox->getImapStream(), $download_email_id, FT_UID);
-            $body = imap_body($this->mailbox->getImapStream(), $download_email_id, FT_UID);
-            print $headers . "\n" . $body;
+        $full_email = $imapClient->load_one_email_fully($download_email_id, $user);
+        if ($full_email !== null) {
+            $filename = $user->address . "-" . $download_email_id . ".eml";
+            $this->viewHandler->downloadEmailAsRfc822($full_email, $filename);
         } else {
-            $this->error(404, 'download error: invalid username/mailid combination');
+            $this->viewHandler->error(404, 'download error: invalid username/mailid combination');
         }
     }
 }
 
 
-class DeleteEmailPage extends Page {
+class DeleteEmailController extends Controller {
     private $email_id;
     private $address;
     private $config_domains;
@@ -108,14 +106,14 @@ class DeleteEmailPage extends Page {
 
         $delete_email_id = filter_var($this->email_id, FILTER_SANITIZE_NUMBER_INT);
         if ($imapClient->delete_email($delete_email_id, $user)) {
-            header("location: ?" . $user->address);
+            $this->viewHandler->done($this->address);
         } else {
-            $this->error(404, 'delete error: invalid username/mailid combination');
+            $this->viewHandler->error(404, 'delete error: invalid username/mailid combination');
         }
     }
 }
 
-class RedirectToRandomAddressPage extends Page {
+class RedirectToRandomAddressController extends Controller {
     private $config_domains;
 
     public function __construct($config_domains) {
@@ -128,7 +126,7 @@ class RedirectToRandomAddressPage extends Page {
 
 }
 
-class DisplayEmailsPage extends Page {
+class DisplayEmailsController extends Controller {
     private $address;
     private $config;
 
@@ -142,16 +140,14 @@ class DisplayEmailsPage extends Page {
         // print emails with html template
         $user = User::parseDomain($this->address, $this->config['blocked_usernames']);
         $this->if_invalid_redirect_to_random($user, $this->config['domains']);
-
-        // Set variables for frontend template:
         $emails = $imapClient->get_emails($user);
-        $config = $this->config;
-        require "frontend.template.php";
+
+        $this->viewHandler->displayEmails($emails, $this->config, $user);
     }
 }
 
-class InvalidRequestPage extends Page {
+class InvalidRequestController extends Controller {
     function invoke(ImapClient $imapClient) {
-        $this->error(400, "Bad Request");
+        $this->viewHandler->error(400, "Bad Request");
     }
 }
diff --git a/src/frontend.template.php b/src/frontend.template.php
index 92e3d59..52b3098 100644
--- a/src/frontend.template.php
+++ b/src/frontend.template.php
@@ -184,7 +184,7 @@ $purifier = new HTMLPurifier($purifier_config);
 
                                     <a class="btn btn-sm btn-outline-danger"
                                        role="button"
-                                       href="?action=delete_email&delete_email_id=<?php echo $safe_email_id; ?>&amp;address=<?php echo $user->address ?>">Delete
+                                       href="?action=delete_email&email_id=<?php echo $safe_email_id; ?>&amp;address=<?php echo $user->address ?>">Delete
                                     </a>
                                 </div>
                             </div>
diff --git a/src/imap_client.php b/src/imap_client.php
index 913af53..af9780d 100644
--- a/src/imap_client.php
+++ b/src/imap_client.php
@@ -54,13 +54,25 @@ class ImapClient {
     }
 
 
+    public function load_one_email_fully($download_email_id, $user) {
+        if ($this->load_one_email($download_email_id, $user) !== null) {
+            $headers = imap_fetchheader($this->mailbox->getImapStream(), $download_email_id, FT_UID);
+            $body = imap_body($this->mailbox->getImapStream(), $download_email_id, FT_UID);
+            return $headers . "\n" . $body;
+        } else {
+            return null;
+        }
+
+    }
+
     /**
      * Load emails using the $mail_ids, the mails have to match the $address in TO or CC.
      * @param $mail_ids array of integer ids
      * @param $user User
      * @return array of emails
      */
-    private function _load_emails(array $mail_ids, User $user) {
+    private
+    function _load_emails(array $mail_ids, User $user) {
         $emails = array();
         foreach ($mail_ids as $id) {
             $mail = $this->mailbox->getMail($id);
@@ -75,7 +87,8 @@ class ImapClient {
     /**
      * deletes messages older than X days.
      */
-    public function delete_old_messages(string $delete_messages_older_than) {
+    public
+    function delete_old_messages(string $delete_messages_older_than) {
         $ids = $this->mailbox->searchMailbox('BEFORE ' . date('d-M-Y', strtotime($delete_messages_older_than)));
         foreach ($ids as $id) {
             $this->mailbox->deleteMail($id);
diff --git a/src/index.php b/src/index.php
index 6d9a6f1..cb8418c 100644
--- a/src/index.php
+++ b/src/index.php
@@ -7,13 +7,14 @@ require_once './backend-libs/autoload.php';
 
 require_once './user.php';
 require_once './imap_client.php';
-require_once './pages.php';
+require_once './controller.php';
 require_once './router.php';
 
 $imapClient = new ImapClient($config['imap']['url'], $config['imap']['username'], $config['imap']['password']);
 
 $router = new Router($_SERVER['REQUEST_METHOD'], $_GET['action'] ?? NULL, $_GET, $_POST, $_SERVER['QUERY_STRING'], $config);
 $page = $router->route();
+$page->setViewHandler(new ServerRenderViewHandler());
 $page->invoke($imapClient);
 
 // delete after each request
diff --git a/src/rest.php b/src/rest.php
new file mode 100644
index 0000000..5f02cc9
--- /dev/null
+++ b/src/rest.php
@@ -0,0 +1,23 @@
+<?php
+# set the new path of config.php (must be in a safe location outside the `public_html`)
+require_once '../../config.php';
+
+# load php dependencies:
+require_once './backend-libs/autoload.php';
+
+require_once './user.php';
+require_once './imap_client.php';
+require_once './controller.php';
+require_once './router.rest.php';
+
+$imapClient = new ImapClient($config['imap']['url'], $config['imap']['username'], $config['imap']['password']);
+
+$router = new RestRouter($_SERVER['REQUEST_METHOD'], $_GET['action'] ?? NULL, $_GET, $_POST, $_SERVER['QUERY_STRING'], $config);
+$page = $router->route();
+$page->setViewHandler(new JsonViewHandler());
+$page->invoke($imapClient);
+
+// delete after each request
+$imapClient->delete_old_messages($config['delete_messages_older_than']);
+
+?>
\ No newline at end of file
diff --git a/src/router.php b/src/router.php
index a4eaaa1..6896e5b 100644
--- a/src/router.php
+++ b/src/router.php
@@ -1,15 +1,15 @@
 <?php
 
-require_once './pages.php';
+require_once './controller.php';
 
 class Router {
 
-    private $method;
-    private $action;
-    private $get_vars;
-    private $post_vars;
-    private $query_string;
-    private $config;
+    protected $method;
+    protected $action;
+    protected $get_vars;
+    protected $post_vars;
+    protected $query_string;
+    protected $config;
 
     public function __construct(string $method, string $action = NULL, array $get_vars, array $post_vars, string $query_string, array $config) {
         $this->method = $method;
@@ -21,30 +21,30 @@ class Router {
     }
 
 
-    function route(): Page {
+    function route(): Controller {
         if ($this->action === "redirect"
             && isset($this->post_vars['username'])
             && isset($this->post_vars['domain'])) {
-            return new RedirectToAddressPage($this->post_vars['username'], $this->post_vars['domain'], $this->config['blocked_usernames']);
+            return new RedirectToAddressController($this->post_vars['username'], $this->post_vars['domain'], $this->config['blocked_usernames']);
 
         } elseif ($this->action === "download_email"
-            && isset($this->get_vars['download_email_id'])
+            && isset($this->get_vars['email_id'])
             && isset($this->get_vars['address'])) {
-            return new DownloadEmailPage($this->get_vars['download_email_id'], $this->get_vars['address'], $this->config['domains'], $this->config['blocked_usernames']);
+            return new DownloadEmailController($this->get_vars['email_id'], $this->get_vars['address'], $this->config['domains'], $this->config['blocked_usernames']);
 
         } elseif ($this->action === "delete_email"
-            && isset($this->get_vars['delete_email_id'])
+            && isset($this->get_vars['email_id'])
             && isset($this->get_vars['address'])) {
-            return new DeleteEmailPage($this->get_vars['delete_email_id'], $this->get_vars['address'], $this->config['domains'], $this->config['blocked_usernames']);
+            return new DeleteEmailController($this->get_vars['email_id'], $this->get_vars['address'], $this->config['domains'], $this->config['blocked_usernames']);
 
         } elseif ($this->action === 'random') {
-            return new RedirectToRandomAddressPage($this->config['domains']);
+            return new RedirectToRandomAddressController($this->config['domains']);
 
         } elseif (!empty($this->query_string)) {
-            return new DisplayEmailsPage($this->query_string, $this->config);
+            return new DisplayEmailsController($this->query_string, $this->config);
 
         } else {
-            return new RedirectToRandomAddressPage($this->config['domains']);
+            return new RedirectToRandomAddressController($this->config['domains']);
         }
     }
 }
\ No newline at end of file
diff --git a/src/router.rest.php b/src/router.rest.php
new file mode 100644
index 0000000..b1ebb0f
--- /dev/null
+++ b/src/router.rest.php
@@ -0,0 +1,30 @@
+<?php
+
+require_once './controller.php';
+require_once './router.php';
+
+
+class RestRouter extends Router {
+
+    function route(): Controller {
+        if ($this->action === "download_email"
+            && isset($this->get_vars['email_id'])
+            && isset($this->get_vars['address'])) {
+            return new DownloadEmailController($this->get_vars['email_id'], $this->get_vars['address'], $this->config['domains'], $this->config['blocked_usernames']);
+
+        } elseif ($this->action === "delete_email"
+            && isset($this->get_vars['email_id'])
+            && isset($this->get_vars['address'])) {
+            return new DeleteEmailController($this->get_vars['email_id'], $this->get_vars['address'], $this->config['domains'], $this->config['blocked_usernames']);
+
+        } elseif ($this->action === 'get_random_username') {
+            return new RedirectToRandomAddressController($this->config['domains']);
+
+        } elseif ($this->action === 'get_emails' && isset($this->get_vars['address'])) {
+            return new DisplayEmailsController($this->get_vars['address'], $this->config);
+
+        } else {
+            return new InvalidRequestController();
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/view.php b/src/view.php
new file mode 100644
index 0000000..58bba7e
--- /dev/null
+++ b/src/view.php
@@ -0,0 +1,79 @@
+<?php
+
+interface ViewHandler {
+    function done($address);
+
+    /**
+     * print error and stop program.
+     * @param $status integer http status
+     * @param $text string error text
+     */
+    function error($status, $text);
+
+    function displayEmails($emails, $config, $user);
+
+    function newAddress($string);
+
+    function downloadEmailAsRfc822($full_email, $filename);
+}
+
+class JsonViewHandler implements ViewHandler {
+
+    private function json($obj) {
+        header('Content-type: application/json');
+
+        // Never cache requests:
+        header("Cache-Control: no-store, no-cache, must-revalidate, max-age=0");
+        header("Cache-Control: post-check=0, pre-check=0", false);
+        header("Pragma: no-cache");
+        print json_encode($obj);
+        die();
+    }
+
+    function done($address) {
+        $this->json(array('status' => "success"));
+    }
+
+    function error($status, $msg) {
+        @http_response_code($status);
+        $this->json(array('status' => "failure", 'error' => $msg));
+    }
+
+    function displayEmails($emails, $config, $user) {
+        $this->json(array('status' => "success", 'emails' => $emails));
+    }
+
+    function newAddress($address) {
+        $this->json(array('status' => "failure", 'address' => $address));
+    }
+
+    function downloadEmailAsRfc822($full_email, $filename) {
+        $this->json(array('status' => "success", 'body' => $full_email));
+    }
+}
+
+class ServerRenderViewHandler implements ViewHandler {
+    function done($address) {
+        header("location: ?" . $address);
+    }
+
+    function error($status, $msg) {
+        @http_response_code($status);
+        die("{'result': 'error', 'error': '$msg'}");
+    }
+
+    function displayEmails($emails, $config, $user) {
+        // Set variables for frontend template: $emails, $config
+        require "frontend.template.php";
+    }
+
+    function newAddress($address) {
+        header("location: ?$address");
+    }
+
+    function downloadEmailAsRfc822($full_email, $filename) {
+        header("Content-Type: message/rfc822; charset=utf-8");
+        header("Content-Disposition: attachment; filename=\"$filename\"");
+        print $full_email;
+    }
+}