diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..bba355f
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,49 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  tests:
+    name: Tests (PHP ${{ matrix.php }})
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        php: ['8.3', '8.4', '8.5']
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php }}
+          coverage: none
+
+      - name: Install dependencies
+        run: composer install --no-interaction --prefer-dist
+
+      - name: Run tests
+        run: composer run tests
+
+  phpstan:
+    name: PHPStan
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.3'
+          coverage: none
+
+      - name: Install dependencies
+        run: composer install --no-interaction --prefer-dist
+
+      - name: Run PHPStan
+        run: composer run phpstan
diff --git a/composer.json b/composer.json
index d4b1655..2962efb 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,8 @@
         "phpunit/phpunit": "^9.5",
         "rector/rector": "^1.2",
         "doctrine/orm": "^3.6",
-        "doctrine/persistence": "^4.1"
+        "doctrine/persistence": "^4.1",
+        "phpstan/phpstan": "^1.12"
     },
     "autoload": {
         "psr-4": {
@@ -37,6 +38,7 @@
     ],
     "minimum-stability": "stable",
     "scripts": {
-        "tests": "phpunit"
+        "tests": "phpunit",
+        "phpstan": "phpstan analyse"
     }
 }
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
new file mode 100644
index 0000000..bc4f631
--- /dev/null
+++ b/phpstan-baseline.neon
@@ -0,0 +1,146 @@
+parameters:
+	ignoreErrors:
+		-
+			message: "#^Call to method load\\(\\) on an unknown class Symfony\\\\Component\\\\DependencyInjection\\\\Loader\\\\XmlFileLoader\\.$#"
+			count: 1
+			path: src/DependencyInjection/MalteHuebnerDataQueryExtension.php
+
+		-
+			message: "#^Instantiated class Symfony\\\\Component\\\\DependencyInjection\\\\Loader\\\\XmlFileLoader not found\\.$#"
+			count: 1
+			path: src/DependencyInjection/MalteHuebnerDataQueryExtension.php
+
+		-
+			message: "#^Deprecated in PHP 8\\.4\\: Parameter \\#3 \\$parameterName \\(string\\) is implicitly nullable via default value null\\.$#"
+			count: 1
+			path: src/Exception/ParameterConverterException.php
+
+		-
+			message: "#^Call to static method getShortnameFromFqcn\\(\\) on an unknown class App\\\\Criticalmass\\\\Util\\\\ClassUtil\\.$#"
+			count: 1
+			path: src/Factory/ConflictResolver/ConflictResolver.php
+
+		-
+			message: "#^Variable \\$parameter in PHPDoc tag @var does not match any variable in the foreach loop\\: \\$parameterCandidate$#"
+			count: 1
+			path: src/Factory/ParameterFactory/ParameterFactory.php
+
+		-
+			message: "#^Variable \\$parameterField in PHPDoc tag @var does not match any variable in the foreach loop\\: \\$fieldName, \\$parameterFields$#"
+			count: 1
+			path: src/Factory/ParameterFactory/ParameterFactory.php
+
+		-
+			message: "#^Call to static method getShortname\\(\\) on an unknown class App\\\\Criticalmass\\\\Util\\\\ClassUtil\\.$#"
+			count: 1
+			path: src/Factory/QueryFactory/QueryFactory.php
+
+		-
+			message: "#^Variable \\$entityField in PHPDoc tag @var does not match any variable in the foreach loop\\: \\$entityFields$#"
+			count: 1
+			path: src/Factory/QueryFactory/QueryFactory.php
+
+		-
+			message: "#^Negated boolean expression is always false\\.$#"
+			count: 1
+			path: src/Factory/ValueAssigner/ValueAssigner.php
+
+		-
+			message: "#^Call to an undefined method ReflectionType\\:\\:getName\\(\\)\\.$#"
+			count: 1
+			path: src/FieldList/EntityFieldList/EntityFieldListFactory.php
+
+		-
+			message: "#^Call to an undefined method ReflectionType\\:\\:getName\\(\\)\\.$#"
+			count: 1
+			path: src/FieldList/ParameterFieldList/ParameterFieldListFactory.php
+
+		-
+			message: "#^Call to an undefined method MalteHuebner\\\\DataQueryBundle\\\\FieldList\\\\AbstractField\\:\\:setParameterName\\(\\)\\.$#"
+			count: 2
+			path: src/FieldList/QueryFieldList/QueryFieldListFactory.php
+
+		-
+			message: "#^Call to an undefined method ReflectionType\\:\\:getName\\(\\)\\.$#"
+			count: 2
+			path: src/FieldList/QueryFieldList/QueryFieldListFactory.php
+
+		-
+			message: "#^Call to method find\\(\\) on an unknown class FOS\\\\ElasticaBundle\\\\Repository\\.$#"
+			count: 1
+			path: src/Finder/Finder.php
+
+		-
+			message: "#^Class MalteHuebner\\\\DataQueryBundle\\\\Finder\\\\AbstractOrmQuery not found\\.$#"
+			count: 1
+			path: src/Finder/Finder.php
+
+		-
+			message: "#^Parameter \\$repository of method MalteHuebner\\\\DataQueryBundle\\\\Finder\\\\Finder\\:\\:__construct\\(\\) has invalid type FOS\\\\ElasticaBundle\\\\Repository\\.$#"
+			count: 1
+			path: src/Finder/Finder.php
+
+		-
+			message: "#^Property MalteHuebner\\\\DataQueryBundle\\\\Finder\\\\Finder\\:\\:\\$repository has unknown class FOS\\\\ElasticaBundle\\\\Repository as its type\\.$#"
+			count: 1
+			path: src/Finder/Finder.php
+
+		-
+			message: "#^Class FOS\\\\ElasticaBundle\\\\Manager\\\\RepositoryManagerInterface not found\\.$#"
+			count: 2
+			path: src/FinderFactory/FinderFactory.php
+
+		-
+			message: "#^Cannot call method addMust\\(\\) on array\\<string, array\\<string, mixed\\>\\>\\|Elastica\\\\Query\\\\AbstractQuery\\.$#"
+			count: 1
+			path: src/Parameter/StartValueParameter.php
+
+		-
+			message: "#^Call to static method getDayEndDateTime\\(\\) on an unknown class App\\\\Criticalmass\\\\Util\\\\DateTimeUtil\\.$#"
+			count: 2
+			path: src/Query/DateQuery.php
+
+		-
+			message: "#^Call to static method getDayStartDateTime\\(\\) on an unknown class App\\\\Criticalmass\\\\Util\\\\DateTimeUtil\\.$#"
+			count: 2
+			path: src/Query/DateQuery.php
+
+		-
+			message: "#^Call to static method getMonthEndDateTime\\(\\) on an unknown class App\\\\Criticalmass\\\\Util\\\\DateTimeUtil\\.$#"
+			count: 2
+			path: src/Query/MonthQuery.php
+
+		-
+			message: "#^Call to static method getMonthStartDateTime\\(\\) on an unknown class App\\\\Criticalmass\\\\Util\\\\DateTimeUtil\\.$#"
+			count: 2
+			path: src/Query/MonthQuery.php
+
+		-
+			message: "#^Call to static method getYearEndDateTime\\(\\) on an unknown class App\\\\Criticalmass\\\\Util\\\\DateTimeUtil\\.$#"
+			count: 2
+			path: src/Query/YearQuery.php
+
+		-
+			message: "#^Call to static method getYearStartDateTime\\(\\) on an unknown class App\\\\Criticalmass\\\\Util\\\\DateTimeUtil\\.$#"
+			count: 2
+			path: src/Query/YearQuery.php
+
+		-
+			message: "#^Access to an undefined property Symfony\\\\Component\\\\Validator\\\\Constraint\\:\\:\\$message\\.$#"
+			count: 2
+			path: src/Validator/BoundingBoxValidator.php
+
+		-
+			message: "#^PHPDoc tag @var above a method has no effect\\.$#"
+			count: 1
+			path: src/Validator/BoundingBoxValidator.php
+
+		-
+			message: "#^Access to an undefined property Symfony\\\\Component\\\\Validator\\\\Constraint\\:\\:\\$message\\.$#"
+			count: 1
+			path: src/Validator/SortableValidator.php
+
+		-
+			message: "#^Variable \\$fieldList in PHPDoc tag @var does not match assigned variable \\$entityFieldList\\.$#"
+			count: 1
+			path: src/Validator/SortableValidator.php
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
new file mode 100644
index 0000000..457dc0e
--- /dev/null
+++ b/phpstan.neon.dist
@@ -0,0 +1,8 @@
+includes:
+    - phpstan-baseline.neon
+
+parameters:
+    level: 5
+    paths:
+        - src
+    reportUnmatchedIgnoredErrors: false