diff --git a/.github/workflows/phpstan.yml b/.github/workflows/phpstan.yml
new file mode 100644
index 0000000..225a807
--- /dev/null
+++ b/.github/workflows/phpstan.yml
@@ -0,0 +1,39 @@
+name: Tests PHPStan in environments
+
+on: [pull_request]
+
+jobs:
+  php82-laravel-latest-phpstan-postgres:
+    runs-on: ubuntu-latest
+    container:
+      image: escolalms/php:8.2
+
+    services:
+      postgres:
+        image: postgres:12
+        env:
+          POSTGRES_USER: postgres
+          POSTGRES_PASSWORD: postgres
+          POSTGRES_DB: test
+          TZ: Europe/Warsaw
+        ports:
+          - 5432:5432
+
+    steps:
+      - name: Instantiate package
+        uses: actions/checkout@v2
+
+      - name: Setup environment
+        run: cp env/postgres/* .
+
+      - name: Update composer
+        run: COMPOSER_ROOT_VERSION=0.9.9 composer update
+
+      - name: Clear config
+        run: vendor/bin/testbench config:clear
+
+      - name: Publish things
+        run: vendor/bin/testbench migrate:fresh
+
+      - name: Run tests
+        run: vendor/bin/phpstan analyse
diff --git a/composer.json b/composer.json
index 32f7cc5..ccd3298 100644
--- a/composer.json
+++ b/composer.json
@@ -10,7 +10,8 @@
   },
   "require-dev": {
     "phpunit/phpunit": "^9.0",
-    "orchestra/testbench": "^6.0"
+    "orchestra/testbench": ">=6.0",
+    "nunomaduro/larastan": "^2.0"
   },
   "license": "MIT",
   "authors": [
diff --git a/phpstan.neon b/phpstan.neon
new file mode 100644
index 0000000..99fcd65
--- /dev/null
+++ b/phpstan.neon
@@ -0,0 +1,10 @@
+includes:
+    - ./vendor/nunomaduro/larastan/extension.neon
+
+parameters:
+
+    paths:
+        - src/
+
+    # The level 9 is the highest level
+    level: 5
diff --git a/src/AuthServiceProvider.php b/src/AuthServiceProvider.php
index 1747e5d..3080166 100644
--- a/src/AuthServiceProvider.php
+++ b/src/AuthServiceProvider.php
@@ -14,7 +14,7 @@ class AuthServiceProvider extends ServiceProvider
         Tag::class => TagPolicy::class,
     ];
 
-    public function boot()
+    public function boot(): void
     {
         $this->registerPolicies();
 
diff --git a/src/Dto/TagDto.php b/src/Dto/TagDto.php
index 9ef06f2..267d16b 100644
--- a/src/Dto/TagDto.php
+++ b/src/Dto/TagDto.php
@@ -38,12 +38,12 @@ public function getModelName() :? string
         return $this->modelName;
     }
 
-    public function getTags()
+    public function getTags(): array
     {
         return $this->tags;
     }
 
-    public function getModelId()
+    public function getModelId(): int
     {
         return $this->modelId;
     }
diff --git a/src/EscolaLmsTagsServiceProvider.php b/src/EscolaLmsTagsServiceProvider.php
index 1d5b7be..3055356 100644
--- a/src/EscolaLmsTagsServiceProvider.php
+++ b/src/EscolaLmsTagsServiceProvider.php
@@ -16,12 +16,15 @@
  */
 class EscolaLmsTagsServiceProvider extends ServiceProvider
 {
-    public $singletons = [
+    /**
+     * @var array<class-string, class-string>
+     */
+    public array $singletons = [
         TagRepositoryContract::class => TagRepository::class,
         TagServiceContract::class => TagService::class
     ];
 
-    public function register()
+    public function register(): void
     {
         $this->mergeConfigFrom(__DIR__ . '/config.php', 'escolalms_tags');
         if (!app()->bound(EscolaLmsSettingsServiceProvider::class)) {
@@ -29,10 +32,11 @@ public function register()
         }
     }
 
-    public function boot()
+    public function boot(): void
     {
         $this->loadRoutesFrom(__DIR__ . '/routes.php');
         $this->loadMigrations();
+        // @phpstan-ignore-next-line
         $this->app['router']->aliasMiddleware('role', RoleMiddleware::class);
         if ($this->app->runningInConsole()) {
             $this->bootForConsole();
@@ -42,7 +46,7 @@ public function boot()
         $this->loadTranslationsFrom(__DIR__ . '/../resources/lang', 'tags');
     }
 
-    protected function bootForConsole()
+    protected function bootForConsole(): void
     {
         $this->publishes([
             __DIR__ . '/config.php' => config_path('escolalms_tags.php'),
diff --git a/src/Http/Controllers/TagsAPIController.php b/src/Http/Controllers/TagsAPIController.php
index cf7cb25..db25b9b 100644
--- a/src/Http/Controllers/TagsAPIController.php
+++ b/src/Http/Controllers/TagsAPIController.php
@@ -69,14 +69,11 @@ public function index(Request $request): JsonResponse
      * Display the specified Tag.
      * GET|HEAD /tags/{tag}
      *
-     * @param $id
      * @return JsonResponse
      */
     public function show(Tag $tag, Request $request): JsonResponse
     {
-        return empty($tag) ?
-            $this->sendError('Tag not found', 404) :
-            $this->sendResponse($tag, 'Tag fetched successfully');
+        return $this->sendResponse($tag, 'Tag fetched successfully');
     }
 
     /**
@@ -101,16 +98,12 @@ public function destroy(TagRemoveRequest $tagRemoveRequest): JsonResponse
     public function unique(Request $request): JsonResponse
     {
         $tags = $this->tagRepository->unique();
-        return $tags ?
-            $this->sendResponse($tags, 'Tags unique fetched successfully') :
-            $this->sendError('Tags not found', 404) ;
+        return $this->sendResponse($tags, 'Tags unique fetched successfully');
     }
 
     public function uniqueAdmin(Request $request): JsonResponse
     {
         $tags = $this->tagRepository->unique();
-        return $tags ?
-            $this->sendResponse($tags, 'Tags unique fetched successfully') :
-            $this->sendError('Tags not found', 404) ;
+        return $this->sendResponse($tags, 'Tags unique fetched successfully');
     }
 }
diff --git a/src/Http/Request/TagInsertRequest.php b/src/Http/Request/TagInsertRequest.php
index 707ea40..71bcb89 100644
--- a/src/Http/Request/TagInsertRequest.php
+++ b/src/Http/Request/TagInsertRequest.php
@@ -12,7 +12,7 @@ class TagInsertRequest extends FormRequest
      *
      * @return bool
      */
-    public function authorize()
+    public function authorize(): bool
     {
         return auth()->user()->can('create', Tag::class);
     }
@@ -20,9 +20,9 @@ public function authorize()
     /**
      * Get the validation rules that apply to the request.
      *
-     * @return array
+     * @return array<string, string>
      */
-    public function rules()
+    public function rules(): array
     {
         return [
             'model_type' => 'required|string',
diff --git a/src/Http/Request/TagRemoveRequest.php b/src/Http/Request/TagRemoveRequest.php
index 177f952..236b765 100644
--- a/src/Http/Request/TagRemoveRequest.php
+++ b/src/Http/Request/TagRemoveRequest.php
@@ -12,7 +12,7 @@ class TagRemoveRequest extends FormRequest
      *
      * @return bool
      */
-    public function authorize()
+    public function authorize(): bool
     {
         return auth()->user()->can('create', Tag::class);
     }
@@ -20,9 +20,9 @@ public function authorize()
     /**
      * Get the validation rules that apply to the request.
      *
-     * @return array
+     * @return array<string, string>
      */
-    public function rules()
+    public function rules(): array
     {
         return [
             'tags' => 'required|array',
diff --git a/src/Models/Tag.php b/src/Models/Tag.php
index 6ae984d..579987e 100644
--- a/src/Models/Tag.php
+++ b/src/Models/Tag.php
@@ -4,6 +4,7 @@
 
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\MorphTo;
 
 /**
  * Class Tag
@@ -31,7 +32,7 @@ class Tag extends Model
     /**
      * The attributes that should be casted to native types.
      *
-     * @var array
+     * @var array<string, string>
      */
     protected $casts = [
         'id' => 'integer',
@@ -43,7 +44,7 @@ class Tag extends Model
     /**
      * Validation rules
      *
-     * @var array
+     * @var array<string, string>
      */
     public static $rules = [
         'title' => 'nullable|string|max:255',
@@ -57,7 +58,7 @@ class Tag extends Model
     /**
      * Get the owning commentable model.
      */
-    public function morphable()
+    public function morphable(): MorphTo
     {
         return $this->morphTo();
     }
diff --git a/src/Policies/TagPolicy.php b/src/Policies/TagPolicy.php
index f4d097f..76ccc93 100644
--- a/src/Policies/TagPolicy.php
+++ b/src/Policies/TagPolicy.php
@@ -22,7 +22,6 @@ public function create(User $user): bool
 
     /**
      * @param User $user
-     * @param Tag $tag
      * @return bool
      */
     public function delete(User $user): bool
diff --git a/src/Repository/TagRepository.php b/src/Repository/TagRepository.php
index 92fd302..ef64ae0 100644
--- a/src/Repository/TagRepository.php
+++ b/src/Repository/TagRepository.php
@@ -47,7 +47,9 @@ public function model() : string
      */
     public function insert(array $tagData) : Tag
     {
-        return $this->model->create($tagData);
+        /** @var Tag $model */
+        $model = $this->model->create($tagData);
+        return $model;
     }
 
     /**
@@ -73,7 +75,9 @@ public function unique(): Collection
     public function uniqueTagsFromActiveCourses(): ?Collection
     {
         return $this->model->select('title')
+            // @phpstan-ignore-next-line
             ->whereHasMorph('morphable', Course::class, function(Builder $query) {
+                // @phpstan-ignore-next-line
                 $query->where('status', '=', CourseStatusEnum::PUBLISHED);
             })
             ->distinct('title')