diff --git a/.php_cs b/.php_cs
deleted file mode 100644
index 23ba165..0000000
--- a/.php_cs
+++ /dev/null
@@ -1,13 +0,0 @@
-<?php
-
-/*
- * In order to make it work, fabpot/php-cs-fixer and sllh/php-cs-fixer-styleci-bridge must be installed globally
- * with composer.
- *
- * @link https://github.com/Soullivaneuh/php-cs-fixer-styleci-bridge
- * @link https://github.com/FriendsOfPHP/PHP-CS-Fixer
- */
-
-use SLLH\StyleCIBridge\ConfigBridge;
-
-return ConfigBridge::create();
diff --git a/.php_cs.dist b/.php_cs.dist
new file mode 100644
index 0000000..8032bb8
--- /dev/null
+++ b/.php_cs.dist
@@ -0,0 +1,14 @@
+
+<?php
+
+$finder = PhpCsFixer\Finder::create()
+    ->exclude('vendor')
+    ->in(__DIR__)
+;
+
+return PhpCsFixer\Config::create()
+    ->setRules([
+         '@Symfony' => true,
+         'array_syntax' => ['syntax' => 'short'],
+    ])
+    ->setFinder($finder);
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
new file mode 100644
index 0000000..776ccd8
--- /dev/null
+++ b/phpstan.neon.dist
@@ -0,0 +1,4 @@
+parameters:
+    level: max
+    paths:
+        - src
diff --git a/src/Client.php b/src/Client.php
index 34570c5..35ded8c 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -2,8 +2,8 @@
 
 namespace Http\Adapter\React;
 
-use Http\Client\HttpClient;
 use Http\Client\HttpAsyncClient;
+use Http\Client\HttpClient;
 use Psr\Http\Message\RequestInterface;
 use Psr\Http\Message\ResponseInterface;
 use React\EventLoop\LoopInterface;
diff --git a/src/Promise.php b/src/Promise.php
index f522d65..ec7d852 100644
--- a/src/Promise.php
+++ b/src/Promise.php
@@ -30,14 +30,14 @@ final class Promise implements HttpPromise
     /**
      * PSR7 received response.
      *
-     * @var ResponseInterface
+     * @var ResponseInterface|null
      */
     private $response;
 
     /**
      * Execution error.
      *
-     * @var Exception
+     * @var HttplugException
      */
     private $exception;
 
@@ -69,7 +69,7 @@ public function __construct(PromiseInterface $promise, LoopInterface $loop, Requ
         $this->request = $request;
         $this->loop = $loop;
         $this->promise = $promise->then(
-            function (?ResponseInterface $response): ResponseInterface {
+            function (?ResponseInterface $response): ?ResponseInterface {
                 $this->response = $response;
                 $this->state = self::FULFILLED;
 
@@ -92,7 +92,8 @@ function ($reason): void {
                 }
 
                 throw $this->exception;
-            });
+            }
+        );
     }
 
     public function then(?callable $onFulfilled = null, ?callable $onRejected = null)
diff --git a/src/ReactFactory.php b/src/ReactFactory.php
index 08085c0..62dbe94 100644
--- a/src/ReactFactory.php
+++ b/src/ReactFactory.php
@@ -2,8 +2,8 @@
 
 namespace Http\Adapter\React;
 
-use React\EventLoop\LoopInterface;
 use React\EventLoop\Factory as EventLoopFactory;
+use React\EventLoop\LoopInterface;
 use React\Http\Browser;
 use React\Socket\ConnectorInterface;
 
@@ -25,8 +25,8 @@ public static function buildEventLoop(): LoopInterface
     /**
      * Build a React Http Client.
      *
-     * @param ConnectorInterface|null $connector Only pass this argument if you need to customize DNS
-     *                                           behaviour.
+     * @param ConnectorInterface|null $connector only pass this argument if you need to customize DNS
+     *                                           behaviour
      */
     public static function buildHttpClient(
         LoopInterface $loop,
diff --git a/tests/AsyncClientTest.php b/tests/AsyncClientTest.php
index bcf9540..7ab4d63 100644
--- a/tests/AsyncClientTest.php
+++ b/tests/AsyncClientTest.php
@@ -2,9 +2,9 @@
 
 namespace Http\Adapter\React\Tests;
 
-use Http\Client\Tests\HttpAsyncClientTest;
 use Http\Adapter\React\Client;
 use Http\Client\HttpAsyncClient;
+use Http\Client\Tests\HttpAsyncClientTest;
 
 /**
  * @author Stéphane Hulard <s.hulard@chstudio.fr>
diff --git a/tests/ClientTest.php b/tests/ClientTest.php
index 57c6614..e2ef2ac 100644
--- a/tests/ClientTest.php
+++ b/tests/ClientTest.php
@@ -2,8 +2,8 @@
 
 namespace Http\Adapter\React\Tests;
 
-use Http\Client\Tests\HttpClientTest;
 use Http\Adapter\React\Client;
+use Http\Client\Tests\HttpClientTest;
 use Psr\Http\Client\ClientInterface;
 
 /**