diff --git a/mirzaev/neuroseti/system/api.php b/mirzaev/neuroseti/system/api.php
new file mode 100644
index 0000000..7214a25
--- /dev/null
+++ b/mirzaev/neuroseti/system/api.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace mirzaev\neuroseti;
+
+/**
+ * API
+ *
+ * Types of neural networks API
+ *
+ * @package mirzaev\neuroseti
+ *
+ * @license http://www.wtfpl.net/ Do What The Fuck You Want To Public License
+ * @author Arsen Mirzaev Tatyano-Muradovich <arsen@mirzaev.sexy>
+ */
+enum api: string
+{
+	case openai = 'OpenAI';
+}
+
diff --git a/mirzaev/neuroseti/system/network.php b/mirzaev/neuroseti/system/network.php
index ceb314f..6d4c2e3 100644
--- a/mirzaev/neuroseti/system/network.php
+++ b/mirzaev/neuroseti/system/network.php
@@ -4,6 +4,9 @@ declare(strict_types=1);
 
 namespace mirzaev\neuroseti;
 
+// Files of the project
+use mirzaev\neuroseti\api;
+
 /**
  * Neural network
  *
@@ -22,22 +25,48 @@ enum network: string
 	case gpt_4_1_nano = 'GPT-4.1 nano';
 	case o_4_mini = 'o4-mini';
 
-	// OpenAI GPT-5
+		// OpenAI GPT-5
 	case gpt_5 = 'GPT-5';
 	case gpt_5_mini = 'GPT-5 mini';
 	case gpt_5_nano = 'GPT-5 nano';
 	case gpt_5_pro = 'GPT-5 pro';
 
-	// OpenAI GPT RealTime
+		// OpenAI GPT RealTime
 	case gpt_realtime = 'GPT realtime';
 	case gpt_realtime_mini = 'GPT realtime mini';
 
-	// OpenAI Sora 2
+		// OpenAI Sora 2
 	case sora_2 = 'Sora 2';
 	case sora_2_pro = 'Sora 2 pro';
 
-	// OpenAI Image Generation
+		// OpenAI Image Generation
 	case gpt_image_1 = 'GPT image 1';
 	case gpt_image_1_mini = 'GPT image 1 mini';
-}
 
+	/**
+	 * API
+	 *
+	 * @return api The neural network API
+	 */
+	public function api(): api
+	{
+		// Exit (success)
+		return match ($this) {
+			static::gpt_4_1,
+			static::gpt_4_1_mini,
+			static::gpt_4_1_nano,
+			static::o_4_mini,
+			static::gpt_5,
+			static::gpt_5_mini,
+			static::gpt_5_nano,
+			static::gpt_5_pro,
+			static::gpt_realtime,
+			static::gpt_realtime_mini,
+			static::sora_2,
+			static::sora_2_pro,
+			static::gpt_image_1,
+			static::gpt_image_1_mini,
+			=> api::openai
+		};
+	}
+}