diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
new file mode 100644
index 0000000..db0657a
--- /dev/null
+++ b/.github/CODEOWNERS
@@ -0,0 +1 @@
+* @Chrico
\ No newline at end of file
diff --git a/.github/workflows/e2e.yml b/.github/workflows/e2e.yml
index c730791..354cc7c 100644
--- a/.github/workflows/e2e.yml
+++ b/.github/workflows/e2e.yml
@@ -1,8 +1,17 @@
 name: E2E Testing
 
-on: 
+on:
   workflow_dispatch:
   push:
+    branches:
+      - master
+      - 1.x
+      - 2.x
+  pull_request:
+    branches:
+      - master
+      - 1.x
+      - 2.x
 
 # Cancels all previous workflow runs for pull requests that have not completed.
 concurrency:
diff --git a/.github/workflows/frontend-qa.yml b/.github/workflows/frontend-qa.yml
index 94de774..ca464a4 100644
--- a/.github/workflows/frontend-qa.yml
+++ b/.github/workflows/frontend-qa.yml
@@ -1,7 +1,16 @@
 name: Static code analysis assets
-on: 
-  push:
+on:
   workflow_dispatch:
+  push:
+    branches:
+      - master
+      - 1.x
+      - 2.x
+  pull_request:
+    branches:
+      - master
+      - 1.x
+      - 2.x
 jobs:
   wp-scripts-lint:
     uses: inpsyde/reusable-workflows/.github/workflows/wp-scripts-lint.yml@main
diff --git a/.github/workflows/php-qa.yml b/.github/workflows/php-qa.yml
index bbda3a1..9bd8d3d 100644
--- a/.github/workflows/php-qa.yml
+++ b/.github/workflows/php-qa.yml
@@ -1,5 +1,16 @@
 name: PHP Quality Assurance
-on: [ push ]
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - master
+      - 1.x
+      - 2.x
+  pull_request:
+    branches:
+      - master
+      - 1.x
+      - 2.x
 jobs:
   lint-php:
     uses: inpsyde/reusable-workflows/.github/workflows/lint-php.yml@main
@@ -12,6 +23,11 @@ jobs:
     uses: inpsyde/reusable-workflows/.github/workflows/coding-standards-php.yml@main
     with:
       PHP_VERSION: '8.1'
+  static-code-analysis-php:
+    uses: inpsyde/reusable-workflows/.github/workflows/static-analysis-php.yml@main
+    with:
+      PSALM_ARGS: '--threads=3'
+      PHP_VERSION: '8.1'
   tests-unit-php:
     runs-on: ubuntu-latest
     if: "!contains(github.event.head_commit.message, 'ci skip')"
diff --git a/README.md b/README.md
index f94e7fd..0928184 100644
--- a/README.md
+++ b/README.md
@@ -13,12 +13,10 @@
 
 ## Documentation
 
-Documentation can be found in [readme.txt](readme.txt).
-
-## Requirements
-
-* WordPress >= 4.6.
-* PHP 8.0 or higher.
+1. [Intro](./docs/01-intro.md)
+2. [Hooks](./docs/02-hooks.md)
+3. [Collectors](./docs/03-collectors.md)
+4. [FAQ](./docs/99-faq.md)
 
 ## How to start development
 
@@ -27,11 +25,9 @@ This plugin does not include build assets and PHP-dependencies. Therefore, after
 **With Yarn:**
 
 ```shell
-yarn install && yarn build:dev
+yarn install && yarn build
 ```
 
-For more information, please refer to the [Symfony Encore docs](https://symfony.com/doc/current/frontend.html#webpack-encore)
-
 ## Testing & Quality
 
 To run all tests you've to install composer dev-dependencies first.
@@ -48,8 +44,6 @@ vendor/bin/phpcs
 vendor/bin/phpunit
 ```
 
-This repository automatically generates a CodeCoverage-report into the `tmp/`-folder, which will not be committed.
-
 ## How to create a release
 
 To create a release go to the `<target>-built` branch and create the tag and the release. 
diff --git a/composer.json b/composer.json
index 52165b9..a92904b 100644
--- a/composer.json
+++ b/composer.json
@@ -27,7 +27,9 @@
     "require-dev": {
         "phpunit/phpunit": "~10",
         "inpsyde/php-coding-standards": "2.0.0-beta.4",
-        "brain/monkey": "^2"
+        "brain/monkey": "^2",
+        "vimeo/psalm": ">=4.8.1@stable",
+        "php-stubs/wordpress-stubs": ">=6.6@stable"
     },
     "autoload": {
         "psr-4": {
diff --git a/psalm.xml b/psalm.xml
new file mode 100644
index 0000000..24d209d
--- /dev/null
+++ b/psalm.xml
@@ -0,0 +1,30 @@
+<?xml version="1.0"?>
+<psalm
+    useDocblockPropertyTypes="true"
+    usePhpDocMethodsWithoutMagicCall="true"
+    strictBinaryOperands="true"
+    hideExternalErrors="true"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="https://getpsalm.org/schema/config"
+    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+>
+    <projectFiles>
+        <directory name="./src"/>
+        <file name="./index.php" />
+        <ignoreFiles>
+            <directory name="vendor" />
+        </ignoreFiles>
+    </projectFiles>
+
+    <stubs>
+        <file name="vendor/php-stubs/wordpress-stubs/wordpress-stubs.php" />
+    </stubs>
+
+    <issueHandlers>
+        <MixedAssignment errorLevel="suppress" />
+        <MissingClosureParamType errorLevel="suppress" />
+        <MissingClosureReturnType errorLevel="suppress" />
+        <UnresolvableInclude errorLevel="suppress" />
+        <UndefinedConstant errorLevel="suppress" />
+    </issueHandlers>
+</psalm>
\ No newline at end of file
diff --git a/resources/svn-assets/banner-1544x500.png b/resources/svn-assets/banner-1544x500.png
index 5c5b7a4..da31f8e 100644
Binary files a/resources/svn-assets/banner-1544x500.png and b/resources/svn-assets/banner-1544x500.png differ
diff --git a/resources/svn-assets/banner-1880x609.png b/resources/svn-assets/banner-1880x609.png
index c76bb4d..91ba085 100644
Binary files a/resources/svn-assets/banner-1880x609.png and b/resources/svn-assets/banner-1880x609.png differ
diff --git a/resources/svn-assets/banner-772x250.png b/resources/svn-assets/banner-772x250.png
index 3fcd36f..164cc4d 100644
Binary files a/resources/svn-assets/banner-772x250.png and b/resources/svn-assets/banner-772x250.png differ
diff --git a/resources/svn-assets/icon-128x128.png b/resources/svn-assets/icon-128x128.png
index 8178298..90b435d 100644
Binary files a/resources/svn-assets/icon-128x128.png and b/resources/svn-assets/icon-128x128.png differ
diff --git a/resources/svn-assets/icon-256x256.png b/resources/svn-assets/icon-256x256.png
index 586b6a7..f45de53 100644
Binary files a/resources/svn-assets/icon-256x256.png and b/resources/svn-assets/icon-256x256.png differ
diff --git a/src/DataLayer/DataLayer.php b/src/DataLayer/DataLayer.php
index 596773b..22a92c1 100644
--- a/src/DataLayer/DataLayer.php
+++ b/src/DataLayer/DataLayer.php
@@ -95,6 +95,7 @@ public function enabledCollectors(): array
     public function data(): array
     {
         $data = [];
+        /** @var DataCollector $collector */
         foreach ($this->registry->all() as $collector) {
             if (!in_array($collector->id(), $this->enabledCollectors(), true)) {
                 continue;
@@ -106,7 +107,10 @@ public function data(): array
                 $settings = $collector->sanitize($settings);
             }
 
-            $data[$collector->id()] = $collector->data($settings);
+            $collectorData = $collector->data($settings);
+            if ($collectorData !== null) {
+                $data[$collector->id()] = $collectorData;
+            }
         }
 
         return $data;
@@ -176,7 +180,6 @@ public function specification(): array
             'label' => __('Enable collectors', 'inpsyde-google-tag-manager'),
             'name' => self::SETTING_ENABLED_COLLECTORS,
             'type' => 'checkbox',
-            'value' => $this->enabledCollectors(),
             'choices' => (function (): array {
                 $choices = [];
                 foreach ($this->registry->all() as $data) {
diff --git a/src/DataLayer/PostDataCollector.php b/src/DataLayer/PostDataCollector.php
index 961c413..9c0a32c 100644
--- a/src/DataLayer/PostDataCollector.php
+++ b/src/DataLayer/PostDataCollector.php
@@ -58,6 +58,7 @@ public function data(array $settings): ?array
         // Post data
         $fields = [];
         foreach ($settings[self::SETTING__POST_FIELDS] as $field) {
+            /** @psalm-suppress DocblockTypeContradiction, RedundantConditionGivenDocblockType */
             $fields[$field] = get_post_field($field) ?? '';
         }
         $fields = array_filter($fields);
@@ -67,6 +68,7 @@ public function data(array $settings): ?array
         // Author data
         $fields = [];
         foreach ($settings[self::SETTING__AUTHOR_FIELDS] as $field) {
+            /** @psalm-suppress DocblockTypeContradiction, RedundantConditionGivenDocblockType */
             $fields[$field] = get_the_author_meta($field) ?? '';
         }
         $fields = array_filter($fields);
@@ -89,7 +91,6 @@ public function specification(): array
             'label' => __('Post fields used in dataLayer', 'inpsyde-google-tag-manager'),
             'name' => self::SETTING__POST_FIELDS,
             'type' => 'checkbox',
-            'value' => $this->settings[self::SETTING__POST_FIELDS],
             'choices' => [
                 [
                     'label' => __('ID', 'inpsyde-google-tag-manager'),
@@ -166,7 +167,6 @@ public function specification(): array
             ),
             'name' => self::SETTING__AUTHOR_FIELDS,
             'type' => 'checkbox',
-            'value' => $this->settings[self::SETTING__AUTHOR_FIELDS],
             'choices' => [
                 [
                     'label' => __('ID', 'inpsyde-google-tag-manager'),
diff --git a/src/DataLayer/UserDataCollector.php b/src/DataLayer/UserDataCollector.php
index 1364078..9a33002 100644
--- a/src/DataLayer/UserDataCollector.php
+++ b/src/DataLayer/UserDataCollector.php
@@ -51,9 +51,6 @@ public function description(): string
         );
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function data(array $settings): ?array
     {
         $isLoggedIn = is_user_logged_in();
diff --git a/src/Provider/AssetProvider.php b/src/Provider/AssetProvider.php
index 778601a..a172a92 100644
--- a/src/Provider/AssetProvider.php
+++ b/src/Provider/AssetProvider.php
@@ -33,6 +33,9 @@ public function run(ContainerInterface $container): bool
             $properties = $container->get(Package::PROPERTIES);
 
             $screen = get_current_screen();
+            if ($screen === null) {
+                return;
+            }
             if ($screen->base !== 'settings_page_' . $properties->baseName()) {
                 return;
             }
diff --git a/src/Provider/DataLayerProvider.php b/src/Provider/DataLayerProvider.php
index f770d92..3c0ccf3 100644
--- a/src/Provider/DataLayerProvider.php
+++ b/src/Provider/DataLayerProvider.php
@@ -36,26 +36,10 @@ public function services(): array
                     $container->get(DataCollectorRegistry::class),
                 );
             },
-            UserDataCollector::class => static function (ContainerInterface $container): UserDataCollector {
-                $settingsRepository = $container->get(SettingsRepository::class);
-
-                return UserDataCollector::new($settingsRepository->option(UserDataCollector::ID));
-            },
-            SiteInfoDataCollector::class => static function (ContainerInterface $container): SiteInfoDataCollector {
-                $settingsRepository = $container->get(SettingsRepository::class);
-
-                return SiteInfoDataCollector::new($settingsRepository->option(SiteInfoDataCollector::ID));
-            },
-            PostDataCollector::class => static function (ContainerInterface $container): PostDataCollector {
-                $settingsRepository = $container->get(SettingsRepository::class);
-
-                return PostDataCollector::new($settingsRepository->option(PostDataCollector::ID));
-            },
-            SearchDataCollector::class => static function (ContainerInterface $container): SearchDataCollector {
-                $settingsRepository = $container->get(SettingsRepository::class);
-
-                return SearchDataCollector::new($settingsRepository->option(SearchDataCollector::ID));
-            },
+            UserDataCollector::class => [UserDataCollector::class, 'new'],
+            SiteInfoDataCollector::class => [SiteInfoDataCollector::class, 'new'],
+            PostDataCollector::class => [PostDataCollector::class, 'new'],
+            SearchDataCollector::class => [SearchDataCollector::class, 'new'],
         ];
     }
 
diff --git a/src/Provider/SettingsProvider.php b/src/Provider/SettingsProvider.php
index 446f619..ff7ef6c 100644
--- a/src/Provider/SettingsProvider.php
+++ b/src/Provider/SettingsProvider.php
@@ -4,7 +4,6 @@
 
 namespace Inpsyde\GoogleTagManager\Provider;
 
-use Inpsyde\GoogleTagManager\Settings\SettingsPage;
 use Inpsyde\GoogleTagManager\Settings\SettingsRepository;
 use Inpsyde\Modularity\Module\ExecutableModule;
 use Inpsyde\Modularity\Module\ModuleClassNameIdTrait;
@@ -30,12 +29,6 @@ public function services(): array
 
                 return SettingsRepository::new($properties->textDomain());
             },
-            SettingsPage::class => static function (ContainerInterface $container): SettingsPage {
-                /** @var PluginProperties $properties */
-                $properties = $container->get(Package::PROPERTIES);
-
-                return SettingsPage::new($properties);
-            },
         ];
     }
 
diff --git a/src/Renderer/DataLayerRenderer.php b/src/Renderer/DataLayerRenderer.php
index 2b94813..a0769b0 100644
--- a/src/Renderer/DataLayerRenderer.php
+++ b/src/Renderer/DataLayerRenderer.php
@@ -36,6 +36,7 @@ public function render(): bool
         $dataLayerJs = sprintf('var %1$s = %1$s || [];', esc_js($dataLayerName));
 
         foreach ($dataLayerPushData as $data) {
+            /** @psalm-suppress DocblockTypeContradiction */
             if (!is_array($data) || count($data) < 1) {
                 continue;
             }
@@ -43,7 +44,7 @@ public function render(): bool
             $dataLayerJs .= sprintf(
                 '%1$s.push(%2$s);',
                 esc_js($dataLayerName),
-                wp_json_encode($data)
+                (string) wp_json_encode($data)
             );
         }
 
diff --git a/src/Rest/DataLayerEndpoint.php b/src/Rest/DataLayerEndpoint.php
index 8fcb479..746fe5b 100644
--- a/src/Rest/DataLayerEndpoint.php
+++ b/src/Rest/DataLayerEndpoint.php
@@ -4,6 +4,7 @@
 
 namespace Inpsyde\GoogleTagManager\Rest;
 
+use Inpsyde\GoogleTagManager\DataLayer\DataCollector;
 use Inpsyde\GoogleTagManager\DataLayer\DataLayer;
 use Inpsyde\GoogleTagManager\Service\DataCollectorRegistry;
 use Inpsyde\GoogleTagManager\Settings\SettingsRepository;
@@ -85,6 +86,7 @@ public function updateDataLayer(\WP_REST_Request $request): \WP_REST_Response
                 $settings[$this->dataLayer->id()] = $dataLayerSettings;
             }
 
+            /** @var DataCollector $collector */
             foreach ($this->registry->all() as $collector) {
                 if (!$collector instanceof SettingsSpecification) {
                     unset($settings[$collector->id()]);
diff --git a/src/Service/DataCollectorRegistry.php b/src/Service/DataCollectorRegistry.php
index 969c56a..eac2938 100644
--- a/src/Service/DataCollectorRegistry.php
+++ b/src/Service/DataCollectorRegistry.php
@@ -35,25 +35,4 @@ public function all(): array
     {
         return $this->collectors;
     }
-
-    public function allFormFields(): array
-    {
-        $fields = [];
-        foreach ($this->all() as $collector) {
-            if (!$collector instanceof SettingsSpecification) {
-                continue;
-            }
-            $fields[] = [
-                'label' => $collector->name(),
-                'description' => $collector->description(),
-                'attributes' => [
-                    'name' => $collector->id(),
-                    'type' => 'collection',
-                ],
-                'elements' => $collector->settingsSpec(),
-            ];
-        }
-
-        return $fields;
-    }
 }
diff --git a/src/Service/RestEndpointRegistry.php b/src/Service/RestEndpointRegistry.php
index c1502b9..1c8abac 100644
--- a/src/Service/RestEndpointRegistry.php
+++ b/src/Service/RestEndpointRegistry.php
@@ -52,9 +52,10 @@ public function addEndpoint(RestEndpoint $endpoint): void
             foreach ($args as $arg) {
                 $name = $arg['entityName'] ?? '';
                 $baseUrl = $arg['entityBaseUrl'] ?? '';
-                if (!$name || !$baseUrl) {
+                if ($name === '' || $baseUrl === '') {
                     continue;
                 }
+                /** @psalm-suppress InvalidPropertyAssignmentValue */
                 $this->entities[$name] = [
                     'label' => (string) $arg['label'],
                     'name' => (string) $name,
@@ -74,7 +75,7 @@ public function addEndpoint(RestEndpoint $endpoint): void
     public function register(): bool
     {
         foreach ($this->endpoints as $base => $endpoint) {
-            if ($this->registered[$base] ?? false) {
+            if (isset($this->registered[$base])) {
                 continue;
             }
             foreach ($endpoint->routes() as $route => $args) {