diff --git a/mobile/index.php b/mobile/index.php
new file mode 100644
index 0000000..1c9b492
--- /dev/null
+++ b/mobile/index.php
@@ -0,0 +1,107 @@
+<?php
+
+/*
+ * Mobile app API
+ */
+
+// The name of the permission needed to log in.
+// Set to null if you don't need it.
+$access_permission = null;
+
+require __DIR__ . "/../required.php";
+
+require __DIR__ . "/../lib/login.php";
+
+header('Content-Type: application/json');
+
+// Allow ping check without authentication
+if ($VARS['action'] == "ping") {
+    exit(json_encode(["status" => "OK"]));
+}
+
+function mobile_enabled() {
+    $client = new GuzzleHttp\Client();
+
+    $response = $client
+            ->request('POST', PORTAL_API, [
+        'form_params' => [
+            'key' => PORTAL_KEY,
+            'action' => "mobileenabled"
+        ]
+    ]);
+
+    if ($response->getStatusCode() > 299) {
+        return false;
+    }
+
+    $resp = json_decode($response->getBody(), TRUE);
+    if ($resp['status'] == "OK" && $resp['mobile'] === TRUE) {
+        return true;
+    } else {
+        return false;
+    }
+}
+
+function mobile_valid($username, $code) {
+    $client = new GuzzleHttp\Client();
+
+    $response = $client
+            ->request('POST', PORTAL_API, [
+        'form_params' => [
+            'key' => PORTAL_KEY,
+            "code" => $code,
+            "username" => $username,
+            'action' => "mobilevalid"
+        ]
+    ]);
+
+    if ($response->getStatusCode() > 299) {
+        return false;
+    }
+
+    $resp = json_decode($response->getBody(), TRUE);
+    if ($resp['status'] == "OK" && $resp['valid'] === TRUE) {
+        return true;
+    } else {
+        return false;
+    }
+}
+
+if (mobile_enabled() !== TRUE) {
+    exit(json_encode(["status" => "ERROR", "msg" => lang("mobile login disabled", false)]));
+}
+
+// Make sure we have a username and access key
+if (is_empty($VARS['username']) || is_empty($VARS['key'])) {
+    http_response_code(401);
+    die(json_encode(["status" => "ERROR", "msg" => "Missing username and/or access key."]));
+}
+
+// Make sure the username and key are actually legit
+if (!mobile_valid($VARS['username'], $VARS['key'])) {
+    engageRateLimit();
+    http_response_code(401);
+    die(json_encode(["status" => "ERROR", "msg" => "Invalid username and/or access key."]));
+}
+
+// Process the action
+switch ($VARS['action']) {
+    case "start_session":
+        // Do a web login.
+        if (user_exists($VARS['username'])) {
+            if (get_account_status($VARS['username']) == "NORMAL") {
+                if (authenticate_user($VARS['username'], $VARS['password'], $autherror)) {
+                    if (is_null($access_permission) || account_has_permission($VARS['username'], $access_permission)) {
+                        doLoginUser($VARS['username'], $VARS['password']);
+                        exit(json_encode(["status" => "OK"]));
+                    } else {
+                        exit(json_encode(["status" => "ERROR", "msg" => lang("no admin permission", false)]));
+                    }
+                }
+            }
+        }
+        exit(json_encode(["status" => "ERROR", "msg" => lang("login incorrect", false)]));
+    default:
+        http_response_code(404);
+        die(json_encode(["status" => "ERROR", "msg" => "The requested action is not available."]));
+}
\ No newline at end of file