diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index 8f66c71..b7d8dff 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -50,6 +50,9 @@ jobs:
           composer install --prefer-dist --no-progress --no-interaction
           if [ -n "$LOG_COVERAGE" ]; then mkdir -p coverage; fi
 
+      - name: Static analysis (PHPStan)
+        run: vendor/bin/phpstan analyse --no-progress
+
       - name: Run tests
         run: |
           vendor/bin/phpunit \
diff --git a/composer.json b/composer.json
index 4eb3c6a..88feeab 100644
--- a/composer.json
+++ b/composer.json
@@ -19,7 +19,8 @@
     },
     "require-dev": {
         "phpunit/phpunit": "^13.0",
-        "mockery/mockery": "^1.6"
+        "mockery/mockery": "^1.6",
+        "phpstan/phpstan": "^2.2"
     },
 
     "bin": [
diff --git a/phpstan.neon b/phpstan.neon
new file mode 100644
index 0000000..91e6453
--- /dev/null
+++ b/phpstan.neon
@@ -0,0 +1,4 @@
+parameters:
+    level: 5
+    paths:
+        - src
diff --git a/src/Config/ConfigLoader.php b/src/Config/ConfigLoader.php
index b7d8b63..70f0bb1 100644
--- a/src/Config/ConfigLoader.php
+++ b/src/Config/ConfigLoader.php
@@ -6,8 +6,6 @@
 
 class ConfigLoader
 {
-    private array $config = [];
-
     /**
      * @throws Exception
      */