diff --git a/.github/workflows/on_pull_request.yml b/.github/workflows/on_pull_request.yml
index acd4281..f01853e 100644
--- a/.github/workflows/on_pull_request.yml
+++ b/.github/workflows/on_pull_request.yml
@@ -31,6 +31,10 @@ jobs:
         run: composer validate --strict --no-check-lock
       - name: Install Composer dependencies (with dev)
         run: composer install --no-progress --no-suggest --prefer-dist --optimize-autoloader
+      - name: Run phpcs
+        run: composer phpcs
+      - name: Run phpstan
+        run: composer phpstan
       - name: Install Composer dependencies (without dev)
         run: composer install --no-progress --no-dev --no-suggest --prefer-dist --optimize-autoloader
 
diff --git a/composer.json b/composer.json
index 5c0b436..97b0c00 100644
--- a/composer.json
+++ b/composer.json
@@ -38,10 +38,12 @@
         "sort-packages": true
     },
     "require-dev": {
+        "phpstan/phpstan": "^2.1",
         "squizlabs/php_codesniffer": "^3.7"
     },
     "scripts": {
         "phpcs": "phpcs",
-        "phpcbf": "phpcbf"
+        "phpcbf": "phpcbf",
+        "phpstan": "phpstan analyse"
     }
 }
diff --git a/phpstan.neon b/phpstan.neon
new file mode 100644
index 0000000..7495716
--- /dev/null
+++ b/phpstan.neon
@@ -0,0 +1,10 @@
+parameters:
+    level: 8
+    paths:
+        - src
+
+    # Ignore tests directory for now
+    excludePaths:
+        - vendor/*
+
+    reportUnmatchedIgnoredErrors: false
diff --git a/src/ToArrayInterface.php b/src/ToArrayInterface.php
index ae69005..f9ac03b 100644
--- a/src/ToArrayInterface.php
+++ b/src/ToArrayInterface.php
@@ -12,7 +12,7 @@ interface ToArrayInterface
     /**
      * Converts object to array
      *
-     * @return array
+     * @return array<string, mixed>
      */
     public function toArray(): array;
 }