diff --git a/.github/workflows/php-cs-fixer.yml b/.github/workflows/php-cs-fixer.yml
new file mode 100644
index 0000000..a83d708
--- /dev/null
+++ b/.github/workflows/php-cs-fixer.yml
@@ -0,0 +1,23 @@
+name: Check & fix styling
+
+on: [push]
+
+jobs:
+  php-cs-fixer:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+        with:
+          ref: ${{ github.head_ref }}
+
+      - name: Run PHP CS Fixer
+        uses: docker://oskarstark/php-cs-fixer-ga
+        with:
+          args: --config=.php-cs-fixer.dist.php --allow-risky=yes
+
+      - name: Commit changes
+        uses: stefanzweifel/git-auto-commit-action@v4
+        with:
+          commit_message: Fix styling
diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index b1761a1..6f8fe3f 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -1,38 +1,36 @@
-name: run-tests
+name: Tests
 
-on:
-  push:
-  pull_request:
+on: [push, pull_request]
 
 jobs:
   test:
-    runs-on: [ubuntu-latest]
+    runs-on: ubuntu-latest
     strategy:
-      fail-fast: false
+      fail-fast: true
       matrix:
-        php: [8.0, 7.4, 7.3, 7.2, 7.1]
-        dependency-version: [prefer-lowest, prefer-stable]
+        php: [8.0, 8.1]
+        stability: [prefer-lowest, prefer-stable]
 
-    name: P${{ matrix.php }} ${{ matrix.dependency-version }}
+    name: P${{ matrix.php }} - ${{ matrix.stability }} - ${{ matrix.os }}
 
     steps:
       - name: Checkout code
         uses: actions/checkout@v2
 
-      - name: Cache dependencies
-        uses: actions/cache@v1
-        with:
-          path: ~/.composer/cache/files
-          key: dependencies-php-${{ matrix.php }}-composer-${{ hashFiles('composer.json') }}
-
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ matrix.php }}
+          extensions: dom, curl, libxml, mbstring, zip, pcntl, pdo, sqlite, pdo_sqlite, bcmath, soap, intl, gd, exif, iconv, imagick, fileinfo
           coverage: none
 
+      - name: Setup problem matchers
+        run: |
+          echo "::add-matcher::${{ runner.tool_cache }}/php.json"
+          echo "::add-matcher::${{ runner.tool_cache }}/phpunit.json"
+
       - name: Install dependencies
-        run: composer update --${{ matrix.dependency-version }} --prefer-dist --no-interaction --no-suggest
+        run: composer update --${{ matrix.stability }} --prefer-dist --no-interaction
 
       - name: Execute tests
         run: vendor/bin/phpunit
diff --git a/.gitignore b/.gitignore
index bb36c67..5c4133d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@ docs
 vendor
 coverage
 phpunit.xml
+.php-cs-fixer.cache
diff --git a/.php-cs-fixer.dist.php b/.php-cs-fixer.dist.php
new file mode 100644
index 0000000..8d8a790
--- /dev/null
+++ b/.php-cs-fixer.dist.php
@@ -0,0 +1,40 @@
+<?php
+
+$finder = Symfony\Component\Finder\Finder::create()
+    ->in([
+        __DIR__ . '/src',
+        __DIR__ . '/tests',
+    ])
+    ->name('*.php')
+    ->notName('*.blade.php')
+    ->ignoreDotFiles(true)
+    ->ignoreVCS(true);
+
+return (new PhpCsFixer\Config())
+    ->setRules([
+        '@PSR12' => true,
+        'array_syntax' => ['syntax' => 'short'],
+        'ordered_imports' => ['sort_algorithm' => 'alpha'],
+        'no_unused_imports' => true,
+        'not_operator_with_successor_space' => true,
+        'trailing_comma_in_multiline' => true,
+        'phpdoc_scalar' => true,
+        'unary_operator_spaces' => true,
+        'binary_operator_spaces' => true,
+        'blank_line_before_statement' => [
+            'statements' => ['break', 'continue', 'declare', 'return', 'throw', 'try'],
+        ],
+        'phpdoc_single_line_var_spacing' => true,
+        'phpdoc_var_without_name' => true,
+        'class_attributes_separation' => [
+            'elements' => [
+                'method' => 'one',
+            ],
+        ],
+        'method_argument_space' => [
+            'on_multiline' => 'ensure_fully_multiline',
+            'keep_multiple_spaces_after_comma' => true,
+        ],
+        'single_trait_insert_per_statement' => true,
+    ])
+    ->setFinder($finder);
diff --git a/composer.json b/composer.json
index 544b90a..22a354e 100644
--- a/composer.json
+++ b/composer.json
@@ -17,11 +17,12 @@
         }
     ],
     "require": {
-        "php": "^7.1|^8.0"
+        "php": "^8.0"
     },
     "require-dev": {
+        "friendsofphp/php-cs-fixer": "^3.2",
         "larapack/dd": "^1.0",
-        "phpunit/phpunit": "^7.0|^8.0|^9.0"
+        "phpunit/phpunit": "^9.0"
     },
     "autoload": {
         "psr-4": {
@@ -33,6 +34,9 @@
             "sixlive\\DotenvEditor\\Tests\\": "tests"
         }
     },
+    "scripts": {
+        "cs": "vendor/bin/php-cs-fixer fix --config=./.php-cs-fixer.dist.php"
+    },
     "config": {
         "sort-packages": true
     }
diff --git a/tests/DotenvEditorTest.php b/tests/DotenvEditorTest.php
index 268bc8c..ca9634e 100644
--- a/tests/DotenvEditorTest.php
+++ b/tests/DotenvEditorTest.php
@@ -25,7 +25,7 @@ public function tearDown(): void
     /** @test */
     public function a_config_value_can_be_set()
     {
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
 
         $editor->set('EXAMPLE_CONFIG', 'foo');
 
@@ -38,7 +38,7 @@ public function a_config_value_can_be_set()
     /** @test */
     public function a_config_value_can_be_unset()
     {
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
 
         $editor->set('EXAMPLE_CONFIG', 'foo');
 
@@ -52,7 +52,7 @@ public function a_config_value_can_be_unset()
     /** @test */
     public function all_config_values_can_be_retrieved()
     {
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
 
         $editor->set('EXAMPLE_CONFIG', 'foo');
         $editor->set('EXAMPLE_CONFIG_2', 'bar');
@@ -68,7 +68,7 @@ public function all_config_values_can_be_retrieved()
     /** @test */
     public function config_values_can_be_saved()
     {
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
 
         $editor->load($this->path);
         $editor->set('EXAMPLE_CONFIG', 'foo');
@@ -81,7 +81,7 @@ public function config_values_can_be_saved()
     public function config_values_can_be_saved_to_a_new_path()
     {
         $newPath = __DIR__.'/tmp/env-new';
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
 
         $editor->load($this->path);
         $editor->set('EXAMPLE_CONFIG', 'foo');
@@ -93,7 +93,7 @@ public function config_values_can_be_saved_to_a_new_path()
     /** @test */
     public function multiple_config_values_can_be_saved()
     {
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
 
         $editor->load($this->path);
         $editor->set('EXAMPLE_CONFIG', 'foo');
@@ -111,7 +111,7 @@ public function multiple_config_values_can_be_saved()
     /** @test */
     public function line_breaks_can_be_added()
     {
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
 
         $editor->load($this->path);
         $editor->set('EXAMPLE_CONFIG', 'foo');
@@ -128,7 +128,7 @@ public function line_breaks_can_be_added()
     /** @test */
     public function headings_can_be_added()
     {
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
 
         $editor->load($this->path);
         $editor->heading('Examples');
@@ -144,7 +144,7 @@ public function headings_can_be_added()
     /** @test */
     public function headings_get_added_with_a_new_line_after_a_non_blank_entry()
     {
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
 
         $editor->load($this->path);
         $editor->set('APP_KEY', 'bar');
@@ -163,7 +163,7 @@ public function headings_get_added_with_a_new_line_after_a_non_blank_entry()
     /** @test */
     public function values_from_files_are_imported_on_load()
     {
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
 
         $editor->load(__DIR__.'/Fixtures/env-example');
 
@@ -180,7 +180,7 @@ public function values_from_files_are_imported_on_load()
     /** @test */
     public function keys_can_be_checked_for()
     {
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
         $editor->load(__DIR__.'/Fixtures/env-example');
 
         $this->assertTrue($editor->has('EXAMPLE_2'));
@@ -190,7 +190,7 @@ public function keys_can_be_checked_for()
     public function configuration_values_can_be_merge_with_an_existing_config()
     {
         copy(__DIR__.'/Fixtures/env-example', $this->path);
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
         $editor->load($this->path);
 
         $editor->heading('Foo');
@@ -210,7 +210,7 @@ public function leaves_blank_settings_as_they_were()
         $fixturePath = __DIR__.'/Fixtures/env-laravel';
         copy($fixturePath, $this->path);
 
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
         $editor->load($this->path);
 
         $editor->set('FOO', 'bar');
@@ -227,7 +227,7 @@ public function an_exception_is_thrown_if_the_file_does_not_exist()
     {
         $this->expectException(InvalidArgumentException::class);
 
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
         $editor->load(__DIR__.'/.env');
     }
 
@@ -237,7 +237,7 @@ public function returns_true_if_file_is_written()
         $fixturePath = __DIR__.'/Fixtures/env-laravel';
         copy($fixturePath, $this->path);
 
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
         $editor->load($this->path);
 
         $this->assertTrue($editor->save());
@@ -248,7 +248,7 @@ public function does_not_modify_app_key()
     {
         $fixturePath = __DIR__.'/Fixtures/env-laravel';
 
-        $editor = new DotenvEditor;
+        $editor = new DotenvEditor();
         $editor->load($fixturePath);
         $this->assertEquals(
             'base64:LPqcjIZ3/T2pO4yrL7vgb6W/+hgyau002onyOKHvzfo=',