diff --git a/ui.php b/ui.php
index 5ab70cd..e4883a0 100644
--- a/ui.php
+++ b/ui.php
@@ -10334,24 +10334,34 @@ private function call(string $method, string $path, array $args = [], $data = fa
 namespace Tqdev\PhpCrudUi\Column {
 
     use Tqdev\PhpCrudUi\Client\CrudApi;
+    use Tqdev\PhpCrudApi\Cache\Cache;
 
     class SpecificationService
     {
         private $api;
+        private $cache;
+        private $ttl;
 
-        public function __construct(CrudApi $api)
+        public function __construct(CrudApi $api, Cache $cache, int $ttl)
         {
             $this->api = $api;
+            $this->cache = $cache;
+            $this->ttl = $ttl;
             $this->definition = $this->getDefinition();
             $this->properties = array();
         }
 
         private function getDefinition(): array
         {
-            if (!isset($_SESSION['definition'])) {
-                $_SESSION['definition'] = $this->api->getOpenApi()?:[];
+            $data = $this->cache->get('Definition');
+            if ($data) {
+                $result = json_decode(gzuncompress($data), true);
+            } else {
+                $result = $this->api->getOpenApi()?:[];
+                $data = gzcompress(json_encode($result));
+                $this->cache->set('Definition', $data, $this->ttl);
             }
-            return $_SESSION['definition'];
+            return $result;
         }
 
         private function resolve($path)
@@ -11437,7 +11447,7 @@ public function __construct(Config $config)
             $api = new CrudApi($config->getUrl());
             $prefix = sprintf('phpcrudui-%s-%s-', substr(md5($config->getUrl()), 0, 12), substr(md5(__FILE__), 0, 12));
             $cache = CacheFactory::create($config->getCacheType(), $prefix, $config->getCachePath());
-            $definition = new SpecificationService($api);
+            $definition = new SpecificationService($api, $cache, $config->getCacheTime());
             $responder = new TemplateResponder($config->getTemplatePath());
             $router = new SimpleRouter($config->getBasePath(), $responder, $cache, $config->getCacheTime(), $config->getDebug());
             $responder->setVariable('base', $router->getBasePath());