diff --git a/README.md b/README.md
index 8b01879..9a3bc53 100644
--- a/README.md
+++ b/README.md
@@ -70,6 +70,11 @@ You can always choose your own strategy for generating numbers:
 $generator->setStrategy();
 ```
 
+Protection duplicate number generation
+--------------------------------------
+
+This tool automatically protects you from generating a duplicate number. To protect you, an automatic lock (see the `baraja-core/lock` library for more information) is used, which allows only one number to be generated at a time, while competing processes in other threads are suspended in the meantime.
+
 📄 License
 -----------
 
diff --git a/composer.json b/composer.json
index ad64dcd..0e4708f 100644
--- a/composer.json
+++ b/composer.json
@@ -9,7 +9,8 @@
 		}
 	],
 	"require": {
-		"php": "^8.0"
+		"php": "^8.0",
+		"baraja-core/lock": "^1.0"
 	},
 	"require-dev": {
 		"phpstan/phpstan": "^0.12.74",
diff --git a/src/VariableGenerator.php b/src/VariableGenerator.php
index 8f446de..0aabc25 100644
--- a/src/VariableGenerator.php
+++ b/src/VariableGenerator.php
@@ -5,6 +5,7 @@
 namespace Baraja\VariableGenerator;
 
 
+use Baraja\Lock\Lock;
 use Baraja\VariableGenerator\Order\DefaultOrderVariableLoader;
 use Baraja\VariableGenerator\Order\OrderEntity;
 use Baraja\VariableGenerator\Strategy\FormatStrategy;
@@ -35,8 +36,10 @@ public function __construct(
 	 * Generate new variable symbol by last variable.
 	 * In case of invalid last symbol or init, use first valid symbol by specific strategy.
 	 */
-	public function generate(?string $last = null): int
+	public function generate(?string $last = null, string $transactionName = 'variable-generator'): int
 	{
+		Lock::wait($transactionName);
+		Lock::startTransaction($transactionName);
 		$last ??= $this->variableLoader->getCurrent();
 		$new = $last === null
 			? $this->strategy->getFirst()