diff --git a/.github/workflows/phpstan.yml b/.github/workflows/phpstan.yml
new file mode 100644
index 0000000..6a1bdf3
--- /dev/null
+++ b/.github/workflows/phpstan.yml
@@ -0,0 +1,44 @@
+name: 'PHPStan Static Analysis'
+
+on:
+    push:
+        branches: [ main, develop ]
+    pull_request:
+        branches: [ main, develop ]
+
+jobs:
+    phpstan:
+        name: PHPStan
+        runs-on: ubuntu-latest
+
+        steps:
+            -   name: Checkout code
+                uses: actions/checkout@v4
+                with:
+                    fetch-depth: 1
+
+            -   name: Setup PHP
+                uses: shivammathur/setup-php@v2
+                with:
+                    php-version: '7.2'
+                    coverage: none
+                    tools: composer:v2
+
+            -   name: Get Composer Cache Directory
+                id: composer-cache
+                run: |
+                    echo "dir=$(composer config cache-files-dir)" >> $GITHUB_OUTPUT
+
+            -   name: Cache Composer dependencies
+                uses: actions/cache@v4
+                with:
+                    path: ${{ steps.composer-cache.outputs.dir }}
+                    key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+                    restore-keys: |
+                        ${{ runner.os }}-composer-
+
+            -   name: Install dependencies
+                run: composer install --prefer-dist --no-progress --no-suggest --no-interaction
+
+            -   name: Run PHPStan
+                run: composer phpstan
diff --git a/composer.json b/composer.json
index 5e9ace7..a234679 100644
--- a/composer.json
+++ b/composer.json
@@ -23,7 +23,9 @@
         "lucatume/di52": "^3.0",
         "lucatume/wp-browser": "^3.0.14",
         "codeception/module-phpbrowser": "^1.0.0",
-        "codeception/module-asserts": "^1.0.0"
+        "codeception/module-asserts": "^1.0.0",
+        "phpstan/phpstan": "^1.12",
+        "szepeviktor/phpstan-wordpress": "^1.3"
     },
     "autoload": {
         "psr-4": {
@@ -45,5 +47,9 @@
             "type": "git",
             "url": "https://github.com/wordpress/wordpress-develop.git"
         }
-    ]
+    ],
+    "scripts": {
+        "phpstan": "phpstan analyse --memory-limit=512M",
+        "phpstan:baseline": "phpstan analyse --generate-baseline=phpstan-baseline.neon --memory-limit=512M"
+    }
 }
diff --git a/composer.lock b/composer.lock
index 429a4ec..c0f19ea 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "2784a3dc6410135037ac4c4588d24cd6",
+    "content-hash": "e030b86c9bdc981348f98418ad2c2e39",
     "packages": [
         {
             "name": "stellarwp/container-contract",
@@ -1894,6 +1894,57 @@
             },
             "time": "2017-03-05T17:38:23+00:00"
         },
+        {
+            "name": "php-stubs/wordpress-stubs",
+            "version": "v6.8.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-stubs/wordpress-stubs.git",
+                "reference": "92e444847d94f7c30f88c60004648f507688acd5"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-stubs/wordpress-stubs/zipball/92e444847d94f7c30f88c60004648f507688acd5",
+                "reference": "92e444847d94f7c30f88c60004648f507688acd5",
+                "shasum": ""
+            },
+            "conflict": {
+                "phpdocumentor/reflection-docblock": "5.6.1"
+            },
+            "require-dev": {
+                "dealerdirect/phpcodesniffer-composer-installer": "^1.0",
+                "nikic/php-parser": "^5.4",
+                "php": "^7.4 || ^8.0",
+                "php-stubs/generator": "^0.8.3",
+                "phpdocumentor/reflection-docblock": "^5.4.1",
+                "phpstan/phpstan": "^2.1",
+                "phpunit/phpunit": "^9.5",
+                "szepeviktor/phpcs-psr-12-neutron-hybrid-ruleset": "^1.1.1",
+                "wp-coding-standards/wpcs": "3.1.0 as 2.3.0"
+            },
+            "suggest": {
+                "paragonie/sodium_compat": "Pure PHP implementation of libsodium",
+                "symfony/polyfill-php80": "Symfony polyfill backporting some PHP 8.0+ features to lower PHP versions",
+                "szepeviktor/phpstan-wordpress": "WordPress extensions for PHPStan"
+            },
+            "type": "library",
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "WordPress function and class declaration stubs for static analysis.",
+            "homepage": "https://github.com/php-stubs/wordpress-stubs",
+            "keywords": [
+                "PHPStan",
+                "static analysis",
+                "wordpress"
+            ],
+            "support": {
+                "issues": "https://github.com/php-stubs/wordpress-stubs/issues",
+                "source": "https://github.com/php-stubs/wordpress-stubs/tree/v6.8.1"
+            },
+            "time": "2025-05-02T12:33:34+00:00"
+        },
         {
             "name": "phpdocumentor/reflection-common",
             "version": "2.2.0",
@@ -2121,6 +2172,64 @@
             },
             "time": "2020-03-05T15:02:03+00:00"
         },
+        {
+            "name": "phpstan/phpstan",
+            "version": "1.12.27",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/phpstan/phpstan.git",
+                "reference": "3a6e423c076ab39dfedc307e2ac627ef579db162"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/3a6e423c076ab39dfedc307e2ac627ef579db162",
+                "reference": "3a6e423c076ab39dfedc307e2ac627ef579db162",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.2|^8.0"
+            },
+            "conflict": {
+                "phpstan/phpstan-shim": "*"
+            },
+            "bin": [
+                "phpstan",
+                "phpstan.phar"
+            ],
+            "type": "library",
+            "autoload": {
+                "files": [
+                    "bootstrap.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "PHPStan - PHP Static Analysis Tool",
+            "keywords": [
+                "dev",
+                "static analysis"
+            ],
+            "support": {
+                "docs": "https://phpstan.org/user-guide/getting-started",
+                "forum": "https://github.com/phpstan/phpstan/discussions",
+                "issues": "https://github.com/phpstan/phpstan/issues",
+                "security": "https://github.com/phpstan/phpstan/security/policy",
+                "source": "https://github.com/phpstan/phpstan-src"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/ondrejmirtes",
+                    "type": "github"
+                },
+                {
+                    "url": "https://github.com/phpstan",
+                    "type": "github"
+                }
+            ],
+            "time": "2025-05-21T20:51:45+00:00"
+        },
         {
             "name": "phpunit/php-code-coverage",
             "version": "5.3.2",
@@ -4851,6 +4960,69 @@
             ],
             "time": "2022-08-02T15:47:23+00:00"
         },
+        {
+            "name": "szepeviktor/phpstan-wordpress",
+            "version": "v1.3.5",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/szepeviktor/phpstan-wordpress.git",
+                "reference": "7f8cfe992faa96b6a33bbd75c7bace98864161e7"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/szepeviktor/phpstan-wordpress/zipball/7f8cfe992faa96b6a33bbd75c7bace98864161e7",
+                "reference": "7f8cfe992faa96b6a33bbd75c7bace98864161e7",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.2 || ^8.0",
+                "php-stubs/wordpress-stubs": "^4.7 || ^5.0 || ^6.0",
+                "phpstan/phpstan": "^1.10.31",
+                "symfony/polyfill-php73": "^1.12.0"
+            },
+            "require-dev": {
+                "composer/composer": "^2.1.14",
+                "dealerdirect/phpcodesniffer-composer-installer": "^1.0",
+                "php-parallel-lint/php-parallel-lint": "^1.1",
+                "phpstan/phpstan-strict-rules": "^1.2",
+                "phpunit/phpunit": "^8.0 || ^9.0",
+                "szepeviktor/phpcs-psr-12-neutron-hybrid-ruleset": "^1.0",
+                "wp-coding-standards/wpcs": "3.1.0 as 2.3.0"
+            },
+            "suggest": {
+                "swissspidy/phpstan-no-private": "Detect usage of internal core functions, classes and methods"
+            },
+            "type": "phpstan-extension",
+            "extra": {
+                "phpstan": {
+                    "includes": [
+                        "extension.neon"
+                    ]
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "SzepeViktor\\PHPStan\\WordPress\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "WordPress extensions for PHPStan",
+            "keywords": [
+                "PHPStan",
+                "code analyse",
+                "code analysis",
+                "static analysis",
+                "wordpress"
+            ],
+            "support": {
+                "issues": "https://github.com/szepeviktor/phpstan-wordpress/issues",
+                "source": "https://github.com/szepeviktor/phpstan-wordpress/tree/v1.3.5"
+            },
+            "time": "2024-06-28T22:27:19+00:00"
+        },
         {
             "name": "theseer/tokenizer",
             "version": "1.2.1",
@@ -5247,15 +5419,15 @@
     ],
     "aliases": [],
     "minimum-stability": "stable",
-    "stability-flags": [],
+    "stability-flags": {},
     "prefer-stable": false,
     "prefer-lowest": false,
     "platform": {
         "ext-json": "*"
     },
-    "platform-dev": [],
+    "platform-dev": {},
     "platform-overrides": {
         "php": "7.2"
     },
-    "plugin-api-version": "2.0.0"
+    "plugin-api-version": "2.6.0"
 }
diff --git a/phpstan.neon b/phpstan.neon
new file mode 100644
index 0000000..5264ea6
--- /dev/null
+++ b/phpstan.neon
@@ -0,0 +1,26 @@
+includes:
+    - vendor/szepeviktor/phpstan-wordpress/extension.neon
+
+parameters:
+    # Level 5 is a good balance between strictness and practicality
+    level: 5
+
+    # Paths to analyze
+    paths:
+        - src
+
+    # Exclude paths
+    excludePaths:
+        - vendor/*
+        - _wordpress/*
+        - _plugins/*
+
+    # Ignore specific errors if needed
+    ignoreErrors:
+        # Add specific error patterns to ignore here if needed
+
+    # PHP version (must be an integer)
+    phpVersion: 70200
+
+    # Treat missing return types as mixed
+    treatPhpDocTypesAsCertain: false
diff --git a/src/Config.php b/src/Config.php
index 1fa76a3..73cd527 100644
--- a/src/Config.php
+++ b/src/Config.php
@@ -82,6 +82,7 @@ public static function setHookPrefix(string $prefix)
     /**
      * @since 1.0.0
      *
+     * @return never
      * @throws ValidationExceptionInterface
      */
     public static function throwValidationException()
@@ -118,6 +119,7 @@ public static function setValidationExceptionClass(string $validationExceptionCl
     /**
      * @since 1.0.0
      *
+     * @return never
      * @throws InvalidArgumentException
      */
     public static function throwInvalidArgumentException()
@@ -162,7 +164,7 @@ public static function initialize()
             return;
         }
 
-        if (empty(self::$container)) {
+        if (self::$container === null) {
             throw new RuntimeException('A service container must be set before initializing the library');
         }
 
diff --git a/src/Exceptions/Contracts/ValidationExceptionInterface.php b/src/Exceptions/Contracts/ValidationExceptionInterface.php
index 8e07a6f..9b49854 100644
--- a/src/Exceptions/Contracts/ValidationExceptionInterface.php
+++ b/src/Exceptions/Contracts/ValidationExceptionInterface.php
@@ -4,7 +4,9 @@
 
 namespace StellarWP\Validation\Exceptions\Contracts;
 
-interface ValidationExceptionInterface
+use Throwable;
+
+interface ValidationExceptionInterface extends Throwable
 {
 
 }
diff --git a/src/Rules/Abstracts/ConditionalRule.php b/src/Rules/Abstracts/ConditionalRule.php
index e17450c..f1b3d17 100644
--- a/src/Rules/Abstracts/ConditionalRule.php
+++ b/src/Rules/Abstracts/ConditionalRule.php
@@ -58,6 +58,7 @@ public static function fromString(string $options = null): ValidationRule
             $conditionSet->and($rule[0], '=', $rule[1]);
         }
 
+        // @phpstan-ignore-next-line
         return new static($conditionSet);
     }
 
diff --git a/src/Rules/DateTime.php b/src/Rules/DateTime.php
index c46d2bb..2a8a735 100644
--- a/src/Rules/DateTime.php
+++ b/src/Rules/DateTime.php
@@ -35,6 +35,7 @@ public static function id(): string
      */
     public static function fromString(string $options = null): ValidationRule
     {
+        // @phpstan-ignore-next-line
         return new static($options);
     }
 
diff --git a/src/ValidationRuleSet.php b/src/ValidationRuleSet.php
index 49f9923..e06b158 100644
--- a/src/ValidationRuleSet.php
+++ b/src/ValidationRuleSet.php
@@ -153,7 +153,7 @@ public function getRule(string $rule)
      *
      * @since 1.0.0
      *
-     * @return void
+     * @return self
      */
     public function removeRuleWithId(string $id): self
     {
@@ -258,14 +258,14 @@ private function sanitizeRule($rule)
             return $rule;
         } elseif (is_string($rule)) {
             return $this->getRuleFromString($rule);
-        } else {
-            Config::throwInvalidArgumentException(
-                sprintf(
-                    'Validation rule must be a string, instance of %s, or a closure',
-                    ValidationRule::class
-                )
-            );
         }
+
+        Config::throwInvalidArgumentException(
+            sprintf(
+                'Validation rule must be a string, instance of %s, or a closure',
+                ValidationRule::class
+            )
+        );
     }
 
     /**
@@ -277,6 +277,7 @@ private function sanitizeRule($rule)
      */
     private function validateClosureRule(Closure $closure)
     {
+        $reflection = null;
         try {
             $reflection = new ReflectionFunction($closure);
         } catch (ReflectionException $e) {