diff --git a/src/DependencyInjection/CompilerPass/ActivatorPass.php b/src/DependencyInjection/CompilerPass/ActivatorPass.php
index cb9860b..5127af3 100644
--- a/src/DependencyInjection/CompilerPass/ActivatorPass.php
+++ b/src/DependencyInjection/CompilerPass/ActivatorPass.php
@@ -17,7 +17,7 @@ class ActivatorPass implements CompilerPassInterface
     /**
      * {@inheritdoc}
      */
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         $bag = $container->getDefinition('flagception.activator.chain_activator');
 
diff --git a/src/DependencyInjection/CompilerPass/ContextDecoratorPass.php b/src/DependencyInjection/CompilerPass/ContextDecoratorPass.php
index 05f8238..ae662ce 100644
--- a/src/DependencyInjection/CompilerPass/ContextDecoratorPass.php
+++ b/src/DependencyInjection/CompilerPass/ContextDecoratorPass.php
@@ -17,7 +17,7 @@ class ContextDecoratorPass implements CompilerPassInterface
     /**
      * {@inheritdoc}
      */
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         $bag = $container->getDefinition('flagception.decorator.chain_decorator');
 
diff --git a/src/DependencyInjection/CompilerPass/ExpressionProviderPass.php b/src/DependencyInjection/CompilerPass/ExpressionProviderPass.php
index 029320c..2a8feb4 100644
--- a/src/DependencyInjection/CompilerPass/ExpressionProviderPass.php
+++ b/src/DependencyInjection/CompilerPass/ExpressionProviderPass.php
@@ -17,7 +17,7 @@ class ExpressionProviderPass implements CompilerPassInterface
     /**
      * {@inheritdoc}
      */
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         $factory = $container->getDefinition('flagception.factory.expression_language_factory');
 
diff --git a/src/DependencyInjection/FlagceptionExtension.php b/src/DependencyInjection/FlagceptionExtension.php
index 16b9823..eed627b 100644
--- a/src/DependencyInjection/FlagceptionExtension.php
+++ b/src/DependencyInjection/FlagceptionExtension.php
@@ -23,7 +23,7 @@ class FlagceptionExtension extends Extension
     /**
      * {@inheritdoc}
      */
-    public function load(array $configs, ContainerBuilder $container)
+    public function load(array $configs, ContainerBuilder $container): void
     {
         $loader = new Loader\YamlFileLoader($container, new FileLocator(__DIR__ . '/../Resources/config'));
         $loader->load('configurators.yml');
diff --git a/src/FlagceptionBundle.php b/src/FlagceptionBundle.php
index a5b5e60..23efbdc 100644
--- a/src/FlagceptionBundle.php
+++ b/src/FlagceptionBundle.php
@@ -19,7 +19,7 @@ class FlagceptionBundle extends Bundle
     /**
      * {@inheritdoc}
      */
-    public function build(ContainerBuilder $container)
+    public function build(ContainerBuilder $container): void
     {
         parent::build($container);
 
diff --git a/src/Profiler/FeatureDataCollector.php b/src/Profiler/FeatureDataCollector.php
index 157b29d..f375aae 100644
--- a/src/Profiler/FeatureDataCollector.php
+++ b/src/Profiler/FeatureDataCollector.php
@@ -47,7 +47,7 @@ public function __construct(ChainActivator $chainActivator, ChainDecorator $chai
     /**
      * {@inheritdoc}
      */
-    public function collect(Request $request, Response $response, Throwable $exception = null)
+    public function collect(Request $request, Response $response, Throwable $exception = null): void
     {
         $this->data = [
             'summary' => [
@@ -200,7 +200,7 @@ public function getName(): string
     /**
      * {@inheritdoc}
      */
-    public function reset()
+    public function reset(): void
     {
         $this->data = [];
     }