diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index db7ce3fd827..39cc4d71785 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -3,14 +3,24 @@ on: [push,pull_request]
 jobs:
   build:
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        php: [ '8.0', '8.1', '8.2' ]
+        typo3: [ '11', '12' ]
+        exclude:
+          - php: '8.0'
+            typo3: '12'
     steps:
       - uses: actions/checkout@v1
       - name: Setup PHP with PECL extension
         uses: shivammathur/setup-php@v2
         with:
-          php-version: '8.1'
+          php-version: ${{ matrix.php }}
           extensions: imagick
       - name: Composer install
-        run: composer install --optimize-autoloader --prefer-dist
+        run: composer require typo3/minimal="^${{ matrix.typo3 }}" --dev --optimize-autoloader --prefer-dist
+      - name: Composer phpstan
+        run: composer phpstan
       - name: Composer test
         run: composer test
diff --git a/Classes/Service/InlineAssets/AbstractInlineAssets.php b/Classes/Service/InlineAssets/AbstractInlineAssets.php
index e503203b4d0..74b547ee718 100644
--- a/Classes/Service/InlineAssets/AbstractInlineAssets.php
+++ b/Classes/Service/InlineAssets/AbstractInlineAssets.php
@@ -16,6 +16,9 @@
  */
 abstract class AbstractInlineAssets extends AbstractService
 {
+    protected string $sitePath;
+    protected ConfigurationService $configurationService;
+
     public function __construct()
     {
         $this->sitePath = Environment::getPublicPath(); // [^/]$
diff --git a/composer.json b/composer.json
index 794baa7779f..15b3c4c33eb 100755
--- a/composer.json
+++ b/composer.json
@@ -30,12 +30,12 @@
 		}
 	],
 	"require": {
-		"php": "^8.0",
+		"php": "~8.0.0 || ~8.1.0 || ~8.2.0",
 		"ext-pdo": "*",
 		"ext-zlib": "*",
-		"typo3/cms-core": "^11.5||^12.4",
-		"typo3/cms-backend": "^11.5||^12.4",
-		"typo3/cms-extensionmanager": "^11.5||^12.4"
+		"typo3/cms-core": "^11.5 || ^12.4",
+		"typo3/cms-backend": "^11.5 || ^12.4",
+		"typo3/cms-extensionmanager": "^11.5 || ^12.4"
 	},
 	"replace": {
 		"typo3-ter/staticfilecache": "self.version"
@@ -49,9 +49,13 @@
 	},
 	"require-dev": {
 		"typo3/testing-framework": "^7.0",
-		"friendsofphp/php-cs-fixer": "^3.16",
+		"friendsofphp/php-cs-fixer": "^3.9",
 		"phpmetrics/phpmetrics": "^2.5",
-		"ssch/typo3-rector": "^1.2"
+		"ssch/typo3-rector": "^1.2",
+		"phpstan/phpstan": "^1.10",
+		"saschaegerer/phpstan-typo3": "^1.8",
+		"andersundsehr/phpstan-git-files": "^1.0",
+		"phpstan/extension-installer": "^1.3"
 	},
 	"suggest": {
 		"lochmueller/seocli": "Scan websites against SEO criteria and/or trigger the indexing process and cache warming in deployment scripts",
@@ -65,7 +69,8 @@
 		"bin-dir": ".Build/bin",
 		"allow-plugins": {
 			"typo3/class-alias-loader": true,
-			"typo3/cms-composer-installers": true
+			"typo3/cms-composer-installers": true,
+			"phpstan/extension-installer": true
 		}
 	},
 	"extra": {
@@ -85,6 +90,9 @@
 		],
 		"test": [
 			"phpunit -c Tests/UnitTests.xml"
+		],
+		"phpstan": [
+			".Build/bin/phpstan"
 		]
 	}
 }
diff --git a/ext_emconf.php b/ext_emconf.php
index ca403842a04..5cd722f3bb5 100755
--- a/ext_emconf.php
+++ b/ext_emconf.php
@@ -2,6 +2,7 @@
 
 declare(strict_types=1);
 
+/** @var string $_EXTKEY */
 $EM_CONF[$_EXTKEY] = [
     'title' => 'StaticFileCache',
     'description' => 'Transparent static file cache solution using mod_rewrite and mod_expires. Increase performance for static pages by a factor of 230!!',
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
new file mode 100644
index 00000000000..0c683e65181
--- /dev/null
+++ b/phpstan-baseline.neon
@@ -0,0 +1,6 @@
+parameters:
+	ignoreErrors:
+		-
+			message: "#^Function brotli_compress not found\\.$#"
+			count: 1
+			path: Classes/Generator/BrotliGenerator.php
diff --git a/phpstan.neon b/phpstan.neon
new file mode 100644
index 00000000000..fb0847063a4
--- /dev/null
+++ b/phpstan.neon
@@ -0,0 +1,7 @@
+includes:
+	- phpstan-baseline.neon
+	- .Build/vendor/andersundsehr/phpstan-git-files/extension.php
+
+parameters:
+	level: 1
+	reportUnmatchedIgnoredErrors: false