diff --git a/install/config_instance.php b/install/config_instance.php
new file mode 100644
index 00000000..66edde42
--- /dev/null
+++ b/install/config_instance.php
@@ -0,0 +1,77 @@
+<?php
+
+#################################################################################
+##              -= YOU MAY NOT REMOVE OR CHANGE THIS NOTICE =-                 ##
+## --------------------------------------------------------------------------- ##
+##  Project:       TravianZ                                                    ##
+##  Filename       config_instance.php                                         ##
+##  Type           : Multi-instance configuration frontend                     ##
+## --------------------------------------------------------------------------- ##
+##  Project        : TravianZ                                                  ##
+##  Source code    : https://github.com/Shadowss/TravianZ                      ##
+#################################################################################
+
+@set_time_limit(0);
+@session_start();
+
+require_once dirname(__DIR__) . '/GameEngine/Instance/InstanceResolver.php';
+require_once dirname(__DIR__) . '/GameEngine/Instance/Instance.php';
+
+$instanceId = strtolower(trim((string) ($_GET['instance'] ?? '')));
+if (!TravianZInstanceResolver::isValid($instanceId)) {
+    http_response_code(400);
+    exit('Invalid instance ID.');
+}
+
+$root = dirname(__DIR__);
+$registryFile = $root . '/instances/registry.json';
+$registry = [];
+if (is_file($registryFile)) {
+    $data = json_decode((string) file_get_contents($registryFile), true);
+    if (is_array($data)) $registry = $data;
+}
+
+if (!isset($registry[$instanceId]) || !is_array($registry[$instanceId])) {
+    http_response_code(404);
+    exit('Instance not found.');
+}
+
+$instance = $registry[$instanceId];
+
+// The existing installer template is the canonical source for all settings.
+// We reuse it instead of maintaining a second copy of the very large form.
+// Values controlled by the instance definition are injected into the rendered
+// form so every world gets its own DB/name/prefix while all other settings stay
+// exactly the same as the normal TravianZ installer.
+$_SESSION['install_random_prefix'] = (string) ($instance['prefix'] ?? ($instanceId . '_'));
+
+ob_start();
+include $root . '/install/templates/config.tpl';
+$html = ob_get_clean();
+
+$html = str_replace('action="process.php"', 'action="process_instance.php"', $html);
+$html = preg_replace(
+    '/(<form\s+action="process_instance\.php"[^>]*>)/i',
+    '$1\n<input type="hidden" name="instance_id" value="' . htmlspecialchars($instanceId, ENT_QUOTES, 'UTF-8') . '">\n<input type="hidden" name="action" value="config">',
+    $html,
+    1
+);
+
+$dbName = (string) ($instance['database'] ?? ('travian_' . $instanceId));
+$prefix = (string) ($instance['prefix'] ?? ($instanceId . '_'));
+$name = (string) ($instance['name'] ?? ('TravianZ ' . strtoupper($instanceId)));
+
+$html = preg_replace('/(<input[^>]+name="servername"[^>]+value=")[^"]*("[^>]*>)/i', '$1' . htmlspecialchars($name, ENT_QUOTES, 'UTF-8') . '$2', $html, 1);
+$html = preg_replace('/(<input[^>]+name="sdb"[^>]+value=")[^"]*("[^>]*>)/i', '$1' . htmlspecialchars($dbName, ENT_QUOTES, 'UTF-8') . '$2', $html, 1);
+$html = preg_replace('/(<input[^>]+name="prefix"[^>]+value=")[^"]*("[^>]*>)/i', '$1' . htmlspecialchars($prefix, ENT_QUOTES, 'UTF-8') . '$2', $html, 1);
+
+$header = '<div style="margin:15px auto;max-width:1100px;padding:14px;background:#e8f5e9;border:1px solid #b7d7b9;font-family:Arial,sans-serif;">'
+    . '<strong>Configuring instance ' . htmlspecialchars($instanceId, ENT_QUOTES, 'UTF-8') . '</strong>'
+    . ' — ' . htmlspecialchars($name, ENT_QUOTES, 'UTF-8')
+    . ' — database: <code>' . htmlspecialchars($dbName, ENT_QUOTES, 'UTF-8') . '</code>'
+    . '<br><a href="multi.php">← Back to multi-instance installer</a>'
+    . '</div>';
+
+$html = preg_replace('/<body([^>]*)>/i', '<body$1>' . $header, $html, 1);
+
+echo $html;