diff --git a/.distignore b/.distignore
index ffb1e0e4..cd7978e7 100644
--- a/.distignore
+++ b/.distignore
@@ -14,5 +14,6 @@
 /package-lock.json
 /phpcs*
 /phpunit*
+/phpstan.*
 /readme.md
-/SECURITY.md
\ No newline at end of file
+/SECURITY.md
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index c20d222e..c940d0db 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -59,6 +59,9 @@ jobs:
             - name: Lint PHP Compatibility
               run: composer lint-compat
 
+            - name: PHPStan
+              run: npm run lint:phpstan
+
     test-php:
         name: Test PHP ${{ matrix.php }} ${{ matrix.wp != '' && format( ' (WP {0}) ', matrix.wp ) || '' }}
         runs-on: ubuntu-latest
diff --git a/.gitignore b/.gitignore
index 6430f0ee..d36ae742 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,4 @@
 /dist/
 /tests/logs/
 .phpunit.result.cache
+phpstan.neon
diff --git a/class-two-factor-compat.php b/class-two-factor-compat.php
index 731a2dff..d7b4f46a 100644
--- a/class-two-factor-compat.php
+++ b/class-two-factor-compat.php
@@ -50,6 +50,6 @@ public function jetpack_rememberme( $rememberme ) {
 	 * @return boolean
 	 */
 	public function jetpack_is_sso_active() {
-		return ( method_exists( 'Jetpack', 'is_module_active' ) && Jetpack::is_module_active( 'sso' ) );
+		return ( class_exists( 'Jetpack' ) && method_exists( 'Jetpack', 'is_module_active' ) && Jetpack::is_module_active( 'sso' ) );
 	}
 }
diff --git a/class-two-factor-core.php b/class-two-factor-core.php
index 51c3cee3..90b6ebaf 100644
--- a/class-two-factor-core.php
+++ b/class-two-factor-core.php
@@ -93,7 +93,7 @@ class Two_Factor_Core {
 	 * @since 0.1-dev
 	 */
 	public static function add_hooks( $compat ) {
-		add_action( 'init', array( __CLASS__, 'get_providers' ) );
+		add_action( 'init', array( __CLASS__, 'get_providers' ) ); // @phpstan-ignore return.void
 		add_action( 'wp_login', array( __CLASS__, 'wp_login' ), 10, 2 );
 		add_filter( 'wp_login_errors', array( __CLASS__, 'maybe_show_reset_password_notice' ) );
 		add_action( 'after_password_reset', array( __CLASS__, 'clear_password_reset_notice' ) );
diff --git a/composer.json b/composer.json
index fe2389c7..2fe8e169 100644
--- a/composer.json
+++ b/composer.json
@@ -31,12 +31,14 @@
     "phpcompatibility/phpcompatibility-wp": "^2.1",
     "phpunit/phpunit": "^8.5|^9.6",
     "spatie/phpunit-watcher": "^1.23",
+    "szepeviktor/phpstan-wordpress": "^1.3",
     "wp-coding-standards/wpcs": "^3.1",
     "yoast/phpunit-polyfills": "^2.0"
   },
   "scripts": {
     "lint": "phpcs",
     "lint-compat": "phpcs -p --standard=PHPCompatibilityWP --runtime-set testVersion 7.2- --extensions=php --ignore='tests/,dist/,includes/Yubico/,vendor/,node_modules/' .",
+    "lint-phpstan": "phpstan analyse --verbose --memory-limit=1G",
     "test": "vendor/bin/phpunit",
     "test:watch": [
       "Composer\\Config::disableProcessTimeout",
diff --git a/composer.lock b/composer.lock
index a4046e68..f1ecd991 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": "a1a44a4d12c7db29c2010274f4d2f36f",
+    "content-hash": "13824921a7208b7752f2a13ecde2ab08",
     "packages": [],
     "packages-dev": [
         {
@@ -1121,6 +1121,54 @@
             },
             "time": "2023-11-22T10:21:01+00:00"
         },
+        {
+            "name": "php-stubs/wordpress-stubs",
+            "version": "v6.6.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-stubs/wordpress-stubs.git",
+                "reference": "86e8753e89d59849276dcdd91b9a7dd78bb4abe2"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-stubs/wordpress-stubs/zipball/86e8753e89d59849276dcdd91b9a7dd78bb4abe2",
+                "reference": "86e8753e89d59849276dcdd91b9a7dd78bb4abe2",
+                "shasum": ""
+            },
+            "require-dev": {
+                "dealerdirect/phpcodesniffer-composer-installer": "^1.0",
+                "nikic/php-parser": "^4.13",
+                "php": "^7.4 || ^8.0",
+                "php-stubs/generator": "^0.8.3",
+                "phpdocumentor/reflection-docblock": "^5.4.1",
+                "phpstan/phpstan": "^1.10.49",
+                "phpunit/phpunit": "^9.5",
+                "szepeviktor/phpcs-psr-12-neutron-hybrid-ruleset": "^1.0",
+                "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/v6.6.0"
+            },
+            "time": "2024-07-17T08:50:38+00:00"
+        },
         {
             "name": "phpcompatibility/php-compatibility",
             "version": "dev-develop",
@@ -1519,6 +1567,64 @@
             ],
             "time": "2024-05-20T13:34:27+00:00"
         },
+        {
+            "name": "phpstan/phpstan",
+            "version": "1.12.3",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/phpstan/phpstan.git",
+                "reference": "0fcbf194ab63d8159bb70d9aa3e1350051632009"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/0fcbf194ab63d8159bb70d9aa3e1350051632009",
+                "reference": "0fcbf194ab63d8159bb70d9aa3e1350051632009",
+                "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": "2024-09-09T08:10:35+00:00"
+        },
         {
             "name": "phpunit/php-code-coverage",
             "version": "7.0.17",
@@ -4589,6 +4695,69 @@
             ],
             "time": "2024-05-31T14:33:22+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": "1.2.3",
diff --git a/package.json b/package.json
index 7ee5b30a..894e834d 100644
--- a/package.json
+++ b/package.json
@@ -12,6 +12,7 @@
     "build": "grunt build",
     "lint": "npm-run-all lint:*",
     "lint:php": "composer lint",
+    "lint:phpstan": "composer lint-phpstan",
     "lint:css": "wp-scripts lint-style ./user-edit.css ./providers/css/",
     "lint:js": "wp-scripts lint-js ./Gruntfile.js ./providers/js/",
     "format": "npm-run-all format:*",
diff --git a/phpstan.dist.neon b/phpstan.dist.neon
new file mode 100644
index 00000000..fc02e7c0
--- /dev/null
+++ b/phpstan.dist.neon
@@ -0,0 +1,10 @@
+includes:
+	- vendor/szepeviktor/phpstan-wordpress/extension.neon
+parameters:
+	level: 0
+	paths:
+		- includes
+		- providers
+		- class-two-factor-compat.php
+		- class-two-factor-core.php
+		- two-factor.php