diff --git a/.editorconfig b/.editorconfig
index 042d009..6537ca4 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -1,15 +1,15 @@
-# This file is for unifying the coding style for different editors and IDEs
-# editorconfig.org
-
 root = true
 
 [*]
-end_of_line = lf
 charset = utf-8
+end_of_line = lf
+insert_final_newline = true
 indent_style = space
 indent_size = 4
 trim_trailing_whitespace = true
-insert_final_newline = true
 
 [*.md]
+trim_trailing_whitespace = false
+
+[*.{yml,yaml}]
 indent_size = 2
diff --git a/.gitattributes b/.gitattributes
index 7ccb1f3..22f739a 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -7,6 +7,5 @@
 .gitattributes    export-ignore
 .gitignore        export-ignore
 .scrutinizer.yml  export-ignore
-.travis.yml       export-ignore
 phpunit.xml.dist  export-ignore
 CONTRIBUTING.md   export-ignore
diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
new file mode 100644
index 0000000..10b997e
--- /dev/null
+++ b/.github/workflows/run-tests.yml
@@ -0,0 +1,46 @@
+name: run-tests
+
+on: [push]
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: true
+      matrix:
+        php: [7.2, 7.3, 7.4]
+        laravel: [6.*]
+        dependency-version: [prefer-lowest, prefer-stable]
+
+    name: PHP ${{ matrix.php }} - ${{ matrix.dependency-version }}
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v1
+
+      - name: Cache dependencies
+        uses: actions/cache@v1
+        with:
+          path: ~/.composer/cache/files
+          key: dependencies-laravel-${{ matrix.laravel }}-php-${{ matrix.php }}-composer-${{ hashFiles('composer.json') }}
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v1
+        with:
+          php-version: ${{ matrix.php }}
+          extensions: curl, mbstring, zip, pcntl, pdo, sqlite, pdo_sqlite, iconv
+          coverage: xdebug
+
+      - name: Install dependencies
+        run: composer update --${{ matrix.dependency-version }} --prefer-dist --no-interaction --no-suggest
+
+      - name: Execute tests
+        run: |
+          mkdir -p build/logs
+          vendor/bin/phpunit --coverage-text --coverage-clover=coverage.clover
+
+      - name: Scrutinizer CI
+        run: |
+          wget https://scrutinizer-ci.com/ocular.phar
+          php ocular.phar code-coverage:upload --format=php-clover coverage.clover
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index b4d863c..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,23 +0,0 @@
-language: php
-
-php:
-  - 7.2
-  - 7.3
-  - nightly
-
-matrix:
-  allow_failures:
-    - php: nightly
-
-before_script:
-  - travis_retry composer self-update
-  - travis_retry composer install --prefer-source --no-interaction
-
-script:
-  - composer validate
-  - mkdir -p build/logs
-  - ./vendor/bin/phpunit --coverage-text --coverage-clover=coverage.clover
-
-after_script:
-  - if [ "$TRAVIS_PHP_VERSION" != "nightly" ]; then wget https://scrutinizer-ci.com/ocular.phar; fi
-  - if [ "$TRAVIS_PHP_VERSION" != "nightly" ]; then php ocular.phar code-coverage:upload --format=php-clover coverage.clover; fi
diff --git a/LICENSE.md b/LICENSE.md
index 35b5760..2ba7e11 100644
--- a/LICENSE.md
+++ b/LICENSE.md
@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2015-2019 | ARCANEDEV <arcanedev.maroc@gmail.com> - LaravelSitemap
+Copyright (c) 2015-2020 | ARCANEDEV <arcanedev.maroc@gmail.com> - LaravelSitemap
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/README.md b/README.md
index 070ab36..dbf850e 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # Laravel Sitemap [![Packagist License][badge_license]](LICENSE.md) [![For Laravel][badge_laravel]][link-github-repo]
 
-[![Travis Status][badge_build]][link-travis]
+[![Github Workflow Status][badge_build]][link-github-status]
 [![Coverage Status][badge_coverage]][link-scrutinizer]
 [![Scrutinizer Code Quality][badge_quality]][link-scrutinizer]
 [![SensioLabs Insight][badge_insight]][link-insight]
@@ -43,7 +43,7 @@ If you discover any security related issues, please email arcanedev.maroc@gmail.
 
 [badge_laravel]:      https://img.shields.io/badge/Laravel-5.4%20to%206.x-orange.svg?style=flat-square
 [badge_license]:      https://img.shields.io/packagist/l/arcanedev/laravel-sitemap.svg?style=flat-square
-[badge_build]:        https://img.shields.io/travis/ARCANEDEV/LaravelSitemap.svg?style=flat-square
+[badge_build]:        https://img.shields.io/github/workflow/status/ARCANEDEV/LaravelSitemap/run-tests?style=flat-square
 [badge_coverage]:     https://img.shields.io/scrutinizer/coverage/g/ARCANEDEV/LaravelSitemap.svg?style=flat-square
 [badge_quality]:      https://img.shields.io/scrutinizer/g/ARCANEDEV/LaravelSitemap.svg?style=flat-square
 [badge_insight]:      https://img.shields.io/sensiolabs/i/40aabf97-8e78-4574-9560-a9ad89704937.svg?style=flat-square
@@ -54,9 +54,9 @@ If you discover any security related issues, please email arcanedev.maroc@gmail.
 
 [link-author]:        https://github.com/arcanedev-maroc
 [link-github-repo]:   https://github.com/ARCANEDEV/LaravelSitemap
+[link-github-status]: https://github.com/ARCANEDEV/LaravelSitemap/actions
 [link-github-issues]: https://github.com/ARCANEDEV/LaravelSitemap/issues
 [link-contributors]:  https://github.com/ARCANEDEV/LaravelSitemap/graphs/contributors
 [link-packagist]:     https://packagist.org/packages/arcanedev/laravel-sitemap
-[link-travis]:        https://travis-ci.org/ARCANEDEV/LaravelSitemap
 [link-scrutinizer]:   https://scrutinizer-ci.com/g/ARCANEDEV/LaravelSitemap/?branch=master
 [link-insight]:       https://insight.sensiolabs.com/projects/40aabf97-8e78-4574-9560-a9ad89704937
diff --git a/composer.json b/composer.json
index a7cd84c..aa2416e 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,7 @@
         "php":               ">=7.2.0",
         "ext-dom":           "*",
         "ext-json":          "*",
-        "arcanedev/support": "^5.0"
+        "arcanedev/support": "^5.1.1"
     },
     "require-dev": {
         "orchestra/testbench":                "^4.0",
diff --git a/helpers.php b/helpers.php
index 1925eb1..ad870c5 100644
--- a/helpers.php
+++ b/helpers.php
@@ -6,9 +6,9 @@
     /**
      * Get the Sitemap Manager instance.
      *
-     * @return SitemapManager
+     * @return \Arcanedev\LaravelSitemap\Contracts\SitemapManager
      */
-    function sitemap() {
+    function sitemap(): SitemapManager {
         return app(SitemapManager::class);
     }
 }
diff --git a/src/Contracts/Entities/ChangeFrequency.php b/src/Contracts/Entities/ChangeFrequency.php
index 3acddc2..0a68d29 100644
--- a/src/Contracts/Entities/ChangeFrequency.php
+++ b/src/Contracts/Entities/ChangeFrequency.php
@@ -1,4 +1,10 @@
-<?php namespace Arcanedev\LaravelSitemap\Contracts\Entities;
+<?php
+
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap\Contracts\Entities;
+
+use Illuminate\Support\Collection;
 
 /**
  * Interface  ChangeFrequency
@@ -31,7 +37,7 @@ interface ChangeFrequency
      *
      * @return \Illuminate\Support\Collection
      */
-    public static function keys();
+    public static function keys(): Collection;
 
     /**
      * Get all the valid frequency values.
@@ -40,18 +46,18 @@ public static function keys();
      *
      * @return \Illuminate\Support\Collection
      */
-    public static function all($locale = null);
+    public static function all(string $locale = null): Collection;
 
     /**
      * Get the translated frequency name.
      *
      * @param  string       $key
-     * @param  string|null  $default
+     * @param  mixed|null   $default
      * @param  string|null  $locale
      *
-     * @return string|null
+     * @return string|mixed|null
      */
-    public static function get($key, $default = null, $locale = null);
+    public static function get(string $key, $default = null, string $locale = null);
 
     /**
      * Check if the given frequency exists.
@@ -60,5 +66,5 @@ public static function get($key, $default = null, $locale = null);
      *
      * @return bool
      */
-    public static function has($key);
+    public static function has(string $key): bool ;
 }
diff --git a/src/Contracts/Entities/Sitemap.php b/src/Contracts/Entities/Sitemap.php
index 129074f..d0cea53 100644
--- a/src/Contracts/Entities/Sitemap.php
+++ b/src/Contracts/Entities/Sitemap.php
@@ -1,8 +1,11 @@
-<?php namespace Arcanedev\LaravelSitemap\Contracts\Entities;
+<?php
+
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap\Contracts\Entities;
 
 use Countable;
-use Illuminate\Contracts\Support\Arrayable;
-use Illuminate\Contracts\Support\Jsonable;
+use Illuminate\Contracts\Support\{Arrayable, Jsonable};
 use Illuminate\Support\Collection;
 use JsonSerializable;
 
@@ -24,30 +27,30 @@ interface Sitemap extends Arrayable, Countable, Jsonable, JsonSerializable
      *
      * @param  string  $path
      *
-     * @return self
+     * @return $this
      */
-    public function setPath($path);
+    public function setPath(string $path);
 
     /**
      * Get the sitemap path.
      *
      * @return string|null
      */
-    public function getPath();
+    public function getPath(): ?string;
 
     /**
      * Get the sitemap's URLs.
      *
      * @return \Illuminate\Support\Collection
      */
-    public function getUrls();
+    public function getUrls(): Collection;
 
     /**
      * Set the URLs Collection.
      *
      * @param  \Illuminate\Support\Collection  $urls
      *
-     * @return self
+     * @return $this
      */
     public function setUrls(Collection $urls);
 
@@ -59,7 +62,7 @@ public function setUrls(Collection $urls);
     /**
      * Make a sitemap instance.
      *
-     * @return self
+     * @return $this
      */
     public static function make();
 
@@ -71,7 +74,7 @@ public static function make();
      *
      * @return \Arcanedev\LaravelSitemap\Entities\Url|null
      */
-    public function getUrl($loc, $default = null);
+    public function getUrl(string $loc, $default = null);
 
     /**
      * Add a sitemap URL to the collection.
@@ -85,11 +88,11 @@ public function add(Url $url);
     /**
      * Add many urls to the collection.
      *
-     * @param  array  $urls
+     * @param  iterable|mixed  $urls
      *
-     * @return self
+     * @return $this
      */
-    public function addMany($urls);
+    public function addMany(iterable $urls);
 
     /**
      * Create and Add a sitemap URL to the collection.
@@ -97,9 +100,9 @@ public function addMany($urls);
      * @param  string    $loc
      * @param  callable  $callback
      *
-     * @return self
+     * @return $this
      */
-    public function create($loc, callable $callback);
+    public function create(string $loc, callable $callback);
 
     /**
      * Check if the url exists in the sitemap items.
@@ -108,19 +111,19 @@ public function create($loc, callable $callback);
      *
      * @return bool
      */
-    public function has($url);
+    public function has(string $url): bool;
 
     /**
      * Check if the number of URLs is exceeded.
      *
      * @return bool
      */
-    public function isExceeded();
+    public function isExceeded(): bool;
 
     /**
      * Chunk the sitemap to multiple chunks if the size is exceeded.
      *
      * @return \Illuminate\Support\Collection
      */
-    public function chunk();
+    public function chunk(): Collection;
 }
diff --git a/src/Contracts/Entities/Url.php b/src/Contracts/Entities/Url.php
index 763491f..afc26d5 100644
--- a/src/Contracts/Entities/Url.php
+++ b/src/Contracts/Entities/Url.php
@@ -1,8 +1,11 @@
-<?php namespace Arcanedev\LaravelSitemap\Contracts\Entities;
+<?php
 
-use DateTime;
-use Illuminate\Contracts\Support\Arrayable;
-use Illuminate\Contracts\Support\Jsonable;
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap\Contracts\Entities;
+
+use DateTimeInterface;
+use Illuminate\Contracts\Support\{Arrayable, Jsonable};
 use JsonSerializable;
 
 /**
@@ -23,14 +26,14 @@ interface Url extends Arrayable, Jsonable, JsonSerializable
      *
      * @return string
      */
-    public function getLoc();
+    public function getLoc(): string;
 
     /**
      * Set the url location.
      *
      * @param  string  $loc
      *
-     * @return self
+     * @return $this
      */
     public function setLoc($loc);
 
@@ -39,7 +42,7 @@ public function setLoc($loc);
      *
      * @return \DateTimeInterface
      */
-    public function getLastMod();
+    public function getLastMod(): DateTimeInterface;
 
     /**
      * Format the url last modification.
@@ -48,7 +51,7 @@ public function getLastMod();
      *
      * @return string
      */
-    public function formatLastMod($format = DateTime::ATOM);
+    public function formatLastMod(string $format = DateTimeInterface::ATOM): string;
 
     /**
      * Set the last modification date.
@@ -56,39 +59,39 @@ public function formatLastMod($format = DateTime::ATOM);
      * @param  string|\DateTimeInterface  $lastModDate
      * @param  string                     $format
      *
-     * @return self
+     * @return $this
      */
-    public function setLastMod($lastModDate, $format = 'Y-m-d H:i:s');
+    public function setLastMod($lastModDate, string $format = 'Y-m-d H:i:s');
 
     /**
      * Get the change frequency.
      *
      * @return string
      */
-    public function getChangeFreq();
+    public function getChangeFreq(): string;
 
     /**
      * Set the change frequency.
      *
      * @param  string  $changeFreq
      *
-     * @return self
+     * @return $this
      */
-    public function setChangeFreq($changeFreq);
+    public function setChangeFreq(string $changeFreq);
 
     /**
      * Get the priority.
      *
      * @return float
      */
-    public function getPriority();
+    public function getPriority(): float;
 
     /**
      * Set the priority.
      *
-     * @param  float  $priority
+     * @param  float|mixed  $priority
      *
-     * @return self
+     * @return $this
      */
     public function setPriority($priority);
 
@@ -97,16 +100,16 @@ public function setPriority($priority);
      *
      * @return string|null
      */
-    public function getTitle();
+    public function getTitle(): ?string;
 
     /**
      * Get the title.
      *
-     * @param  string  $title
+     * @param  string|null  $title
      *
-     * @return self
+     * @return $this
      */
-    public function setTitle($title);
+    public function setTitle(?string $title);
 
     /**
      * Get an attribute from the container.
@@ -124,9 +127,9 @@ public function get($key, $default = null);
      * @param  string  $key
      * @param  mixed   $value
      *
-     * @return self
+     * @return $this
      */
-    public function set($key, $value);
+    public function set(string $key, $value);
 
     /* -----------------------------------------------------------------
      |  Main Methods
@@ -138,7 +141,7 @@ public function set($key, $value);
      *
      * @param  string  $loc
      *
-     * @return \Arcanedev\LaravelSitemap\Entities\Url
+     * @return $this
      */
     public static function make($loc);
 
@@ -147,7 +150,7 @@ public static function make($loc);
      *
      * @param  array  $attributes
      *
-     * @return \Arcanedev\LaravelSitemap\Entities\Url
+     * @return $this
      */
     public static function makeFromArray(array $attributes);
 
@@ -158,5 +161,5 @@ public static function makeFromArray(array $attributes);
      *
      * @return bool
      */
-    public function has($key);
+    public function has(string $key): bool;
 }
diff --git a/src/Contracts/SitemapManager.php b/src/Contracts/SitemapManager.php
index 21e1848..eb61237 100644
--- a/src/Contracts/SitemapManager.php
+++ b/src/Contracts/SitemapManager.php
@@ -1,10 +1,15 @@
-<?php namespace Arcanedev\LaravelSitemap\Contracts;
+<?php
+
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap\Contracts;
 
 use Arcanedev\LaravelSitemap\Contracts\Entities\Sitemap;
 use Countable;
-use Illuminate\Contracts\Support\Arrayable;
-use Illuminate\Contracts\Support\Jsonable;
+use Illuminate\Contracts\Support\{Arrayable, Jsonable};
+use Illuminate\Support\Collection;
 use JsonSerializable;
+use Symfony\Component\HttpFoundation\Response;
 
 /**
  * Interface  SitemapManager
@@ -24,7 +29,7 @@ interface SitemapManager extends Arrayable, Countable, Jsonable, JsonSerializabl
      *
      * @param  string  $format
      *
-     * @return self
+     * @return $this
      */
     public function format($format);
 
@@ -39,9 +44,9 @@ public function format($format);
      * @param  string    $name
      * @param  callable  $callback
      *
-     * @return self
+     * @return $this
      */
-    public function create($name, callable $callback);
+    public function create(string $name, callable $callback);
 
     /**
      * Add a sitemap to the collection.
@@ -49,16 +54,16 @@ public function create($name, callable $callback);
      * @param  string                                                $name
      * @param  \Arcanedev\LaravelSitemap\Contracts\Entities\Sitemap  $sitemap
      *
-     * @return self
+     * @return $this
      */
-    public function add($name, Sitemap $sitemap);
+    public function add(string $name, Sitemap $sitemap);
 
     /**
      * Get the sitemaps collection.
      *
      * @return \Illuminate\Support\Collection
      */
-    public function all();
+    public function all(): Collection;
 
     /**
      * Get a sitemap instance.
@@ -66,9 +71,9 @@ public function all();
      * @param  string      $name
      * @param  mixed|null  $default
      *
-     * @return \Arcanedev\LaravelSitemap\Entities\Sitemap|null
+     * @return \Arcanedev\LaravelSitemap\Entities\Sitemap|mixed|null
      */
-    public function get($name, $default = null);
+    public function get(string $name, $default = null);
 
     /**
      * Check if a sitemap exists.
@@ -77,14 +82,14 @@ public function get($name, $default = null);
      *
      * @return bool
      */
-    public function has($name);
+    public function has(string $name): bool;
 
     /**
      * Remove a sitemap from the collection by key.
      *
      * @param  string|array  $names
      *
-     * @return self
+     * @return $this
      */
     public function forget($names);
 
@@ -95,7 +100,7 @@ public function forget($names);
      *
      * @return string|null
      */
-    public function render($name = null);
+    public function render(string $name = null): ?string;
 
     /**
      * Save the sitemaps.
@@ -103,9 +108,9 @@ public function render($name = null);
      * @param  string       $path
      * @param  string|null  $name
      *
-     * @return self
+     * @return $this
      */
-    public function save($path, $name = null);
+    public function save(string $path, string $name = null);
 
     /**
      * Render the Http response.
@@ -114,7 +119,7 @@ public function save($path, $name = null);
      * @param  int     $status
      * @param  array   $headers
      *
-     * @return \Illuminate\Contracts\Routing\ResponseFactory|\Symfony\Component\HttpFoundation\Response
+     * @return \Illuminate\Http\Response|mixed
      */
-    public function respond($name = null, $status = 200, array $headers = []);
+    public function respond(string $name = null, int $status = Response::HTTP_OK, array $headers = []);
 }
diff --git a/src/Entities/ChangeFrequency.php b/src/Entities/ChangeFrequency.php
index 71fe6b2..5144a30 100644
--- a/src/Entities/ChangeFrequency.php
+++ b/src/Entities/ChangeFrequency.php
@@ -1,4 +1,8 @@
-<?php namespace Arcanedev\LaravelSitemap\Entities;
+<?php
+
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap\Entities;
 
 use Arcanedev\LaravelSitemap\Contracts\Entities\ChangeFrequency as ChangeFrequencyContract;
 use Illuminate\Support\Collection;
@@ -21,7 +25,7 @@ class ChangeFrequency implements ChangeFrequencyContract
      *
      * @return \Illuminate\Support\Collection
      */
-    public static function keys()
+    public static function keys(): Collection
     {
         return new Collection([
             static::ALWAYS,
@@ -37,11 +41,11 @@ public static function keys()
     /**
      * Get all the valid frequency values.
      *
-     * @param  string|null $locale
+     * @param  string|null  $locale
      *
      * @return \Illuminate\Support\Collection
      */
-    public static function all($locale = null)
+    public static function all(string $locale = null): Collection
     {
         return static::keys()->mapWithKeys(function ($key) use ($locale) {
             return [$key => trans("sitemap::frequencies.$key", [], $locale)];
@@ -55,9 +59,9 @@ public static function all($locale = null)
      * @param  string|null  $default
      * @param  string|null  $locale
      *
-     * @return string|null
+     * @return string|mixed|null
      */
-    public static function get($key, $default = null, $locale = null)
+    public static function get($key, $default = null, string $locale = null)
     {
         return static::all($locale)->get($key, $default);
     }
@@ -65,11 +69,11 @@ public static function get($key, $default = null, $locale = null)
     /**
      * Check if the given frequency exists.
      *
-     * @param  string $key
+     * @param  string  $key
      *
      * @return bool
      */
-    public static function has($key)
+    public static function has(string $key): bool
     {
         return static::keys()->flip()->has($key);
     }
diff --git a/src/Entities/Sitemap.php b/src/Entities/Sitemap.php
index 4e60533..602c5a6 100644
--- a/src/Entities/Sitemap.php
+++ b/src/Entities/Sitemap.php
@@ -1,4 +1,8 @@
-<?php namespace Arcanedev\LaravelSitemap\Entities;
+<?php
+
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap\Entities;
 
 use Arcanedev\LaravelSitemap\Contracts\Entities\Sitemap as SitemapContract;
 use Illuminate\Support\Collection;
@@ -46,9 +50,9 @@ public function __construct()
      *
      * @param  string  $path
      *
-     * @return self
+     * @return $this
      */
-    public function setPath($path)
+    public function setPath(string $path)
     {
         $this->path = $path;
 
@@ -60,7 +64,7 @@ public function setPath($path)
      *
      * @return string|null
      */
-    public function getPath()
+    public function getPath(): ?string
     {
         return $this->path;
     }
@@ -70,7 +74,7 @@ public function getPath()
      *
      * @return \Illuminate\Support\Collection
      */
-    public function getUrls()
+    public function getUrls(): Collection
     {
         return $this->urls;
     }
@@ -80,7 +84,7 @@ public function getUrls()
      *
      * @param  \Illuminate\Support\Collection  $urls
      *
-     * @return self
+     * @return $this
      */
     public function setUrls(Collection $urls)
     {
@@ -97,7 +101,7 @@ public function setUrls(Collection $urls)
     /**
      * Make a sitemap instance.
      *
-     * @return self
+     * @return $this
      */
     public static function make()
     {
@@ -112,7 +116,7 @@ public static function make()
      *
      * @return \Arcanedev\LaravelSitemap\Entities\Url|null
      */
-    public function getUrl($loc, $default = null)
+    public function getUrl(string $loc, $default = null)
     {
         return $this->getUrls()->get($loc, $default);
     }
@@ -134,11 +138,11 @@ public function add(UrlContract $url)
     /**
      * Add many urls to the collection.
      *
-     * @param  array|\Illuminate\Support\Collection  $urls
+     * @param  iterable|mixed  $urls
      *
-     * @return self
+     * @return $this
      */
-    public function addMany($urls)
+    public function addMany(iterable $urls)
     {
         foreach ($urls as $url) {
             $this->add($url);
@@ -153,9 +157,9 @@ public function addMany($urls)
      * @param  string    $loc
      * @param  callable  $callback
      *
-     * @return self
+     * @return $this
      */
-    public function create($loc, callable $callback)
+    public function create(string $loc, callable $callback)
     {
         return $this->add(tap(Url::make($loc), $callback));
     }
@@ -167,7 +171,7 @@ public function create($loc, callable $callback)
      *
      * @return bool
      */
-    public function has($url)
+    public function has(string $url): bool
     {
         return $this->urls->has($url);
     }
@@ -177,7 +181,7 @@ public function has($url)
      *
      * @return int
      */
-    public function count()
+    public function count(): int
     {
         return $this->urls->count();
     }
@@ -187,7 +191,7 @@ public function count()
      *
      * @return array
      */
-    public function toArray()
+    public function toArray(): array
     {
         return $this->getUrls()->values()->toArray();
     }
@@ -199,7 +203,7 @@ public function toArray()
      *
      * @return string
      */
-    public function toJson($options = 0)
+    public function toJson($options = 0): string
     {
         return json_encode($this->jsonSerialize(), $options);
     }
@@ -209,7 +213,7 @@ public function toJson($options = 0)
      *
      * @return array
      */
-    public function jsonSerialize()
+    public function jsonSerialize(): array
     {
         return $this->toArray();
     }
@@ -219,7 +223,7 @@ public function jsonSerialize()
      *
      * @return bool
      */
-    public function isExceeded()
+    public function isExceeded(): bool
     {
         return $this->count() > $this->getMaxSize();
     }
@@ -229,15 +233,19 @@ public function isExceeded()
      *
      * @return \Illuminate\Support\Collection
      */
-    public function chunk()
+    public function chunk(): Collection
     {
-        return $this->urls->chunk($this->getMaxSize())->mapWithKeys(function ($item, $index) {
-            $pathInfo = pathinfo($this->getPath());
-            $index    = $index + 1;
-            $path     = $pathInfo['dirname'].'/'.$pathInfo['filename'].'-'.$index.'.'.$pathInfo['extension'];
+        return $this->urls
+            ->chunk($this->getMaxSize())
+            ->mapWithKeys(function ($item, $index) {
+                $pathInfo = pathinfo($this->getPath());
+                $index    = $index + 1;
+                $path     = $pathInfo['dirname'].'/'.$pathInfo['filename'].'-'.$index.'.'.$pathInfo['extension'];
 
-            return [$index => (new Sitemap)->setPath($path)->setUrls($item)];
-        });
+                return [
+                    $index => (new Sitemap)->setPath($path)->setUrls($item),
+                ];
+            });
     }
 
     /* -----------------------------------------------------------------
@@ -250,8 +258,8 @@ public function chunk()
      *
      * @return int
      */
-    protected function getMaxSize()
+    protected function getMaxSize(): int
     {
-        return config('sitemap.urls-max-size', 50000);
+        return (int) config('sitemap.urls-max-size', 50000);
     }
 }
diff --git a/src/Entities/Url.php b/src/Entities/Url.php
index 2d8c462..08df6e3 100644
--- a/src/Entities/Url.php
+++ b/src/Entities/Url.php
@@ -1,8 +1,13 @@
-<?php namespace Arcanedev\LaravelSitemap\Entities;
+<?php
+
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap\Entities;
 
 use Arcanedev\LaravelSitemap\Contracts\Entities\Url as UrlContract;
 use Arcanedev\LaravelSitemap\Exceptions\SitemapException;
 use DateTime;
+use DateTimeInterface;
 use Illuminate\Support\{Arr, Fluent};
 
 /**
@@ -47,7 +52,7 @@ public function __construct($attributes = [])
      *
      * @return string
      */
-    public function getLoc()
+    public function getLoc(): string
     {
         return $this->escape($this->get('loc'));
     }
@@ -57,7 +62,7 @@ public function getLoc()
      *
      * @param  string  $loc
      *
-     * @return self
+     * @return $this
      */
     public function setLoc($loc)
     {
@@ -69,7 +74,7 @@ public function setLoc($loc)
      *
      * @return \DateTimeInterface
      */
-    public function getLastMod()
+    public function getLastMod(): DateTimeInterface
     {
         return $this->get('lastmod');
     }
@@ -81,7 +86,7 @@ public function getLastMod()
      *
      * @return string
      */
-    public function formatLastMod($format = DateTime::ATOM)
+    public function formatLastMod(string $format = DateTimeInterface::ATOM): string
     {
         return $this->getLastMod()->format($format);
     }
@@ -92,9 +97,9 @@ public function formatLastMod($format = DateTime::ATOM)
      * @param  string|\DateTimeInterface  $lastModDate
      * @param  string                     $format
      *
-     * @return self
+     * @return $this
      */
-    public function setLastMod($lastModDate, $format = 'Y-m-d H:i:s')
+    public function setLastMod($lastModDate, string $format = 'Y-m-d H:i:s')
     {
         if (is_string($lastModDate))
             $lastModDate = DateTime::createFromFormat($format, $lastModDate);
@@ -107,7 +112,7 @@ public function setLastMod($lastModDate, $format = 'Y-m-d H:i:s')
      *
      * @return string
      */
-    public function getChangeFreq()
+    public function getChangeFreq(): string
     {
         return $this->get('changefreq');
     }
@@ -117,9 +122,9 @@ public function getChangeFreq()
      *
      * @param  string  $changeFreq
      *
-     * @return self
+     * @return $this
      */
-    public function setChangeFreq($changeFreq)
+    public function setChangeFreq(string $changeFreq)
     {
         return $this->set('changefreq', strtolower(trim($changeFreq)));
     }
@@ -129,7 +134,7 @@ public function setChangeFreq($changeFreq)
      *
      * @return float
      */
-    public function getPriority()
+    public function getPriority(): float
     {
         return $this->get('priority');
     }
@@ -137,9 +142,9 @@ public function getPriority()
     /**
      * Set the priority.
      *
-     * @param  float  $priority
+     * @param  float|mixed  $priority
      *
-     * @return self
+     * @return $this
      */
     public function setPriority($priority)
     {
@@ -153,7 +158,7 @@ public function setPriority($priority)
      *
      * @return string|null
      */
-    public function getTitle()
+    public function getTitle(): ?string
     {
         return $this->escape($this->get('title'));
     }
@@ -161,11 +166,11 @@ public function getTitle()
     /**
      * Get the title.
      *
-     * @param  string  $title
+     * @param  string|null  $title
      *
-     * @return self
+     * @return $this
      */
-    public function setTitle($title)
+    public function setTitle(?string $title)
     {
         return $this->set('title', $title);
     }
@@ -176,9 +181,9 @@ public function setTitle($title)
      * @param  string  $key
      * @param  mixed   $value
      *
-     * @return self
+     * @return $this
      */
-    public function set($key, $value)
+    public function set(string $key, $value)
     {
         $this->attributes[$key] = $value;
 
@@ -195,7 +200,7 @@ public function set($key, $value)
      *
      * @param  string  $loc
      *
-     * @return \Arcanedev\LaravelSitemap\Entities\Url
+     * @return $this
      */
     public static function make($loc)
     {
@@ -207,7 +212,7 @@ public static function make($loc)
      *
      * @param  array  $attributes
      *
-     * @return \Arcanedev\LaravelSitemap\Entities\Url
+     * @return $this
      */
     public static function makeFromArray(array $attributes)
     {
@@ -221,7 +226,7 @@ public static function makeFromArray(array $attributes)
      *
      * @return bool
      */
-    public function has($key)
+    public function has(string $key): bool
     {
         return ! is_null($this->get($key));
     }
@@ -246,18 +251,19 @@ public function toArray()
     /**
      * Escape the given value.
      *
-     * @param  string  $value
+     * @param  string|mixed  $value
      *
-     * @return string
+     * @return string|null
      */
     protected function escape($value)
     {
         if (is_null($value))
             return $value;
 
-        return config('sitemap.escaping', true)
-            ? htmlentities($value, ENT_XML1, 'UTF-8')
-            : $value;
+        if (config('sitemap.escaping', true))
+            $value = htmlentities($value, ENT_XML1, 'UTF-8');
+
+        return $value;
     }
 
     /**
@@ -269,9 +275,9 @@ protected function escape($value)
      *
      * @throws \Arcanedev\LaravelSitemap\Exceptions\SitemapException
      */
-    protected function checkLoc($loc)
+    protected function checkLoc($loc): string
     {
-        if (is_null($loc) || ! is_string($loc))
+        if ( ! is_string($loc))
             throw new SitemapException('The [loc] attribute is required and must be string value.');
 
         return $loc;
@@ -280,13 +286,13 @@ protected function checkLoc($loc)
     /**
      * Check the priority value.
      *
-     * @param  float  $priority
+     * @param  float|mixed  $priority
      *
      * @return float
      *
      * @throws \Arcanedev\LaravelSitemap\Exceptions\SitemapException
      */
-    protected function checkPriority($priority)
+    protected function checkPriority($priority): float
     {
         if ( ! is_numeric($priority))
             throw new SitemapException("The [priority] value must be numeric.");
diff --git a/src/Exceptions/SitemapException.php b/src/Exceptions/SitemapException.php
index 149e41d..e64c039 100644
--- a/src/Exceptions/SitemapException.php
+++ b/src/Exceptions/SitemapException.php
@@ -1,4 +1,8 @@
-<?php namespace Arcanedev\LaravelSitemap\Exceptions;
+<?php
+
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap\Exceptions;
 
 use Exception;
 
diff --git a/src/LaravelSitemapServiceProvider.php b/src/LaravelSitemapServiceProvider.php
index afa2640..97985ac 100644
--- a/src/LaravelSitemapServiceProvider.php
+++ b/src/LaravelSitemapServiceProvider.php
@@ -1,5 +1,10 @@
-<?php namespace Arcanedev\LaravelSitemap;
+<?php
 
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap;
+
+use Arcanedev\LaravelSitemap\Contracts\SitemapManager as SitemapManagerContract;
 use Arcanedev\Support\Providers\PackageServiceProvider;
 use Illuminate\Contracts\Support\DeferrableProvider;
 
@@ -37,7 +42,7 @@ public function register(): void
 
         $this->registerConfig();
 
-        $this->singleton(Contracts\SitemapManager::class, SitemapManager::class);
+        $this->singleton(SitemapManagerContract::class, SitemapManager::class);
     }
 
 
@@ -59,7 +64,7 @@ public function boot(): void
     public function provides(): array
     {
         return [
-            Contracts\SitemapManager::class,
+            SitemapManagerContract::class,
         ];
     }
 }
diff --git a/src/SitemapBuilder.php b/src/SitemapBuilder.php
index d9c4706..f467da1 100644
--- a/src/SitemapBuilder.php
+++ b/src/SitemapBuilder.php
@@ -1,4 +1,8 @@
-<?php namespace Arcanedev\LaravelSitemap;
+<?php
+
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap;
 
 use Arcanedev\LaravelSitemap\Contracts\Entities\Sitemap;
 use DOMDocument;
@@ -24,13 +28,13 @@ class SitemapBuilder
      */
     public static function make()
     {
-        return new static();
+        return new static;
     }
 
     /**
      * Build the sitemap.
      *
-     * @param  string                          $name
+     * @param  string|null                     $name
      * @param  \Illuminate\Support\Collection  $sitemaps
      * @param  string                          $format
      *
@@ -38,7 +42,7 @@ public static function make()
      *
      * @return string|null
      */
-    public function build($name, Collection $sitemaps, $format)
+    public function build(?string $name, Collection $sitemaps, string $format): ?string
     {
         if ($sitemaps->isEmpty())
             return null;
@@ -75,7 +79,7 @@ public function build($name, Collection $sitemaps, $format)
      *
      * @return string|null
      */
-    protected function renderSitemap($format, Sitemap $sitemap = null, $key = null)
+    protected function renderSitemap(string $format, Sitemap $sitemap = null, string $key = null)
     {
         if (is_null($sitemap))
             return null;
@@ -85,9 +89,10 @@ protected function renderSitemap($format, Sitemap $sitemap = null, $key = null)
 
         $chunks = $sitemap->chunk();
 
-        return is_null($key)
-            ? static::renderSitemapIndex($format, $chunks)
-            : static::renderSitemap($format, $chunks->get($key));
+        if (is_null($key))
+            return static::renderSitemapIndex($format, $chunks);
+
+        return static::renderSitemap($format, $chunks->get($key));
     }
 
     /**
@@ -100,7 +105,7 @@ protected function renderSitemap($format, Sitemap $sitemap = null, $key = null)
      *
      * @return string|null
      */
-    protected function renderSitemapIndex($format, $sitemaps)
+    protected function renderSitemapIndex(string $format, Collection $sitemaps): ?string
     {
         return static::render($format, 'sitemap-index', compact('sitemaps'));
     }
@@ -116,9 +121,11 @@ protected function renderSitemapIndex($format, $sitemaps)
      *
      * @return string|null
      */
-    protected function render($format, $type, array $data)
+    protected function render(string $format, string $type, array $data): ?string
     {
-        switch ($format= strtolower(trim($format))) {
+        $format = strtolower(trim($format));
+
+        switch ($format) {
             case 'xml':
             case 'rss':
                 return static::renderXml($format, $type, $data);
@@ -140,7 +147,7 @@ protected function render($format, $type, array $data)
      *
      * @return string
      */
-    protected function renderXml($format, $type, array $data)
+    protected function renderXml(string $format, string $type, array $data): string
     {
         return tap(new DOMDocument('1.0'), function (DOMDocument $document) use ($format, $type, $data) {
             $document->preserveWhiteSpace = false;
@@ -162,7 +169,7 @@ protected function renderXml($format, $type, array $data)
      *
      * @return string
      */
-    protected function renderView($type, $format, array $data)
+    protected function renderView(string $type, string $format, array $data): string
     {
         return view("sitemap::{$type}.{$format}", $data)->render();
     }
diff --git a/src/SitemapManager.php b/src/SitemapManager.php
index 30af65c..6641ac2 100644
--- a/src/SitemapManager.php
+++ b/src/SitemapManager.php
@@ -1,9 +1,14 @@
-<?php namespace Arcanedev\LaravelSitemap;
+<?php
+
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap;
 
 use Arcanedev\LaravelSitemap\Contracts\Entities\Sitemap as SitemapContract;
 use Arcanedev\LaravelSitemap\Contracts\SitemapManager as SitemapManagerContract;
 use Arcanedev\LaravelSitemap\Entities\Sitemap;
 use Illuminate\Support\{Arr, Collection, Str};
+use Symfony\Component\HttpFoundation\Response;
 
 /**
  * Class     SitemapManager
@@ -47,7 +52,7 @@ public function __construct()
      *
      * @param  string  $format
      *
-     * @return self
+     * @return $this
      */
     public function format($format)
     {
@@ -67,9 +72,9 @@ public function format($format)
      * @param  string    $name
      * @param  callable  $callback
      *
-     * @return self
+     * @return $this
      */
-    public function create($name, callable $callback)
+    public function create(string $name, callable $callback)
     {
         return $this->add($name, tap(Sitemap::make()->setPath($name), $callback));
     }
@@ -80,9 +85,9 @@ public function create($name, callable $callback)
      * @param  string                                                $name
      * @param  \Arcanedev\LaravelSitemap\Contracts\Entities\Sitemap  $sitemap
      *
-     * @return self
+     * @return $this
      */
-    public function add($name, SitemapContract $sitemap)
+    public function add(string $name, SitemapContract $sitemap)
     {
         $this->sitemaps->put($name, $sitemap);
 
@@ -94,7 +99,7 @@ public function add($name, SitemapContract $sitemap)
      *
      * @return \Illuminate\Support\Collection
      */
-    public function all()
+    public function all(): Collection
     {
         return $this->sitemaps;
     }
@@ -105,9 +110,9 @@ public function all()
      * @param  string      $name
      * @param  mixed|null  $default
      *
-     * @return mixed
+     * @return \Arcanedev\LaravelSitemap\Entities\Sitemap|mixed|null
      */
-    public function get($name, $default = null)
+    public function get(string $name, $default = null)
     {
         return $this->sitemaps->get($name, $default);
     }
@@ -119,7 +124,7 @@ public function get($name, $default = null)
      *
      * @return bool
      */
-    public function has($name)
+    public function has(string $name): bool
     {
         if ( ! Str::contains($name, '.'))
             return $this->sitemaps->has($name);
@@ -140,7 +145,7 @@ public function has($name)
      *
      * @param  string|array  $names
      *
-     * @return self
+     * @return $this
      */
     public function forget($names)
     {
@@ -154,7 +159,7 @@ public function forget($names)
      *
      * @return int
      */
-    public function count()
+    public function count(): int
     {
         return $this->sitemaps->count();
     }
@@ -168,7 +173,7 @@ public function count()
      *
      * @return string|null
      */
-    public function render($name = null)
+    public function render(string $name = null): ?string
     {
         return SitemapBuilder::make()->build($name, $this->sitemaps, $this->format);
     }
@@ -181,9 +186,9 @@ public function render($name = null)
      *
      * @throws \Throwable
      *
-     * @return self
+     * @return $this
      */
-    public function save($path, $name = null)
+    public function save(string $path, string $name = null)
     {
         if ($this->sitemaps->isEmpty())
             return $this;
@@ -208,9 +213,9 @@ public function save($path, $name = null)
      *
      * @throws \Throwable
      *
-     * @return \Illuminate\Contracts\Routing\ResponseFactory|\Symfony\Component\HttpFoundation\Response
+     * @return \Illuminate\Http\Response|mixed
      */
-    public function respond($name = null, $status = 200, array $headers = [])
+    public function respond(string $name = null, int $status = Response::HTTP_OK, array $headers = [])
     {
         return response($this->render($name), $status, array_merge($this->getResponseHeaders(), $headers));
     }
@@ -220,7 +225,7 @@ public function respond($name = null, $status = 200, array $headers = [])
      *
      * @return array
      */
-    public function toArray()
+    public function toArray(): array
     {
         return $this->all()->toArray();
     }
@@ -232,7 +237,7 @@ public function toArray()
      *
      * @return string
      */
-    public function toJson($options = 0)
+    public function toJson($options = 0): string
     {
         return json_encode($this->jsonSerialize(), $options);
     }
@@ -242,7 +247,7 @@ public function toJson($options = 0)
      *
      * @return array
      */
-    public function jsonSerialize()
+    public function jsonSerialize(): array
     {
         return $this->toArray();
     }
@@ -255,7 +260,7 @@ public function jsonSerialize()
      *
      * @throws \Throwable
      */
-    private function saveMultiple($path, $sitemap)
+    private function saveMultiple(string $path, SitemapContract $sitemap)
     {
         $pathInfo = pathinfo($path);
         $chunks   = $sitemap->chunk();
@@ -263,7 +268,7 @@ private function saveMultiple($path, $sitemap)
         foreach ($chunks as $key => $item) {
             file_put_contents(
                 $pathInfo['dirname'].DS.$pathInfo['filename'].'-'.$key.'.'.$pathInfo['extension'],
-                SitemapBuilder::make()->build($key, $chunks, $this->format)
+                SitemapBuilder::make()->build((string) $key, $chunks, $this->format)
             );
         }
     }
@@ -273,7 +278,7 @@ private function saveMultiple($path, $sitemap)
      *
      * @return array
      */
-    protected function getResponseHeaders()
+    protected function getResponseHeaders(): array
     {
         return Arr::get([
             'xml' => ['Content-Type' => 'application/xml'],
diff --git a/tests/Entities/ChangeFrequencyTest.php b/tests/Entities/ChangeFrequencyTest.php
index 8fd7b74..128443e 100644
--- a/tests/Entities/ChangeFrequencyTest.php
+++ b/tests/Entities/ChangeFrequencyTest.php
@@ -1,4 +1,8 @@
-<?php namespace Arcanedev\LaravelSitemap\Tests\Entities;
+<?php
+
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap\Tests\Entities;
 
 use Arcanedev\LaravelSitemap\Entities\ChangeFrequency;
 use Arcanedev\LaravelSitemap\Tests\TestCase;
@@ -18,7 +22,7 @@ class ChangeFrequencyTest extends TestCase
      */
 
     /** @test */
-    public function it_can_get_all_keys()
+    public function it_can_get_all_keys(): void
     {
         $frequencies = ChangeFrequency::keys();
 
@@ -38,7 +42,7 @@ public function it_can_get_all_keys()
     }
 
     /** @test */
-    public function it_can_get_all_translated_frequencies()
+    public function it_can_get_all_translated_frequencies(): void
     {
         $frequencies = ChangeFrequency::all();
 
@@ -58,7 +62,7 @@ public function it_can_get_all_translated_frequencies()
     }
 
     /** @test */
-    public function it_can_get_all_translated_frequencies_with_a_given_locale()
+    public function it_can_get_all_translated_frequencies_with_a_given_locale(): void
     {
         $frequencies = ChangeFrequency::all('fr');
 
@@ -78,7 +82,7 @@ public function it_can_get_all_translated_frequencies_with_a_given_locale()
     }
 
     /** @test */
-    public function it_can_get_one_translated_frequency()
+    public function it_can_get_one_translated_frequency(): void
     {
         $key = ChangeFrequency::ALWAYS;
 
@@ -97,7 +101,7 @@ public function it_can_get_one_translated_frequency()
     }
 
     /** @test */
-    public function it_can_check_if_frequency_exists()
+    public function it_can_check_if_frequency_exists(): void
     {
         foreach (ChangeFrequency::keys() as $key) {
             static::assertTrue(ChangeFrequency::has($key));
diff --git a/tests/Entities/SitemapTest.php b/tests/Entities/SitemapTest.php
index 30c882b..64a3058 100644
--- a/tests/Entities/SitemapTest.php
+++ b/tests/Entities/SitemapTest.php
@@ -1,8 +1,17 @@
-<?php namespace Arcanedev\LaravelSitemap\Tests\Entities;
+<?php
+
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap\Tests\Entities;
 
 use Arcanedev\LaravelSitemap\Contracts\Entities\ChangeFrequency;
+use Arcanedev\LaravelSitemap\Contracts\Entities\Sitemap as SitemapContract;
+use DateTime;
 use Arcanedev\LaravelSitemap\Entities\{Sitemap, Url};
 use Arcanedev\LaravelSitemap\Tests\TestCase;
+use Countable;
+use Illuminate\Contracts\Support\{Arrayable, Jsonable};
+use JsonSerializable;
 use Spatie\Snapshots\MatchesSnapshots;
 
 /**
@@ -53,15 +62,15 @@ protected function tearDown(): void
      */
 
     /** @test */
-    public function it_can_be_instantiated()
+    public function it_can_be_instantiated(): void
     {
         $expectations = [
-            \Countable::class,
-            \JsonSerializable::class,
-            \Illuminate\Contracts\Support\Arrayable::class,
-            \Illuminate\Contracts\Support\Jsonable::class,
-            \Arcanedev\LaravelSitemap\Contracts\Entities\Sitemap::class,
-            \Arcanedev\LaravelSitemap\Entities\Sitemap::class,
+            Countable::class,
+            JsonSerializable::class,
+            Arrayable::class,
+            Jsonable::class,
+            SitemapContract::class,
+            Sitemap::class,
         ];
 
         foreach ($expectations as $expected) {
@@ -72,17 +81,17 @@ public function it_can_be_instantiated()
     }
 
     /** @test */
-    public function it_can_make()
+    public function it_can_make(): void
     {
         $map = Sitemap::make();
 
         $expectations = [
-            \Countable::class,
-            \JsonSerializable::class,
-            \Illuminate\Contracts\Support\Arrayable::class,
-            \Illuminate\Contracts\Support\Jsonable::class,
-            \Arcanedev\LaravelSitemap\Contracts\Entities\Sitemap::class,
-            \Arcanedev\LaravelSitemap\Entities\Sitemap::class,
+            Countable::class,
+            JsonSerializable::class,
+            Arrayable::class,
+            Jsonable::class,
+            SitemapContract::class,
+            Sitemap::class,
         ];
 
         foreach ($expectations as $expected) {
@@ -93,17 +102,17 @@ public function it_can_make()
     }
 
     /** @test */
-    public function it_can_add_url_to_the_collection()
+    public function it_can_add_url_to_the_collection(): void
     {
         static::assertSame(0, $this->sitemap->count());
 
-        $this->sitemap->add($this->createUrlSample());
+        $this->sitemap->add(static::createUrlSample());
 
         static::assertSame(1, $this->sitemap->count());
     }
 
     /** @test */
-    public function it_can_create_and_add_url_to_collection()
+    public function it_can_create_and_add_url_to_collection(): void
     {
         static::assertSame(0, $this->sitemap->count());
 
@@ -127,9 +136,9 @@ public function it_can_create_and_add_url_to_collection()
     }
 
     /** @test */
-    public function it_can_check_if_has_an_existing_url()
+    public function it_can_check_if_has_an_existing_url(): void
     {
-        $url = $this->createUrlSample();
+        $url = static::createUrlSample();
 
         static::assertFalse($this->sitemap->has($url->getLoc()));
 
@@ -139,9 +148,9 @@ public function it_can_check_if_has_an_existing_url()
     }
 
     /** @test */
-    public function it_can_get_url_by_its_loc()
+    public function it_can_get_url_by_its_loc(): void
     {
-        $url = $this->createUrlSample();
+        $url = static::createUrlSample();
 
         static::assertNull($this->sitemap->getUrl($url->getLoc()));
 
@@ -151,11 +160,11 @@ public function it_can_get_url_by_its_loc()
     }
 
     /** @test */
-    public function it_can_convert_to_array()
+    public function it_can_convert_to_array(): void
     {
         static::assertSame([], $this->sitemap->toArray());
 
-        $this->sitemap->add($this->createUrlSample());
+        $this->sitemap->add(static::createUrlSample());
 
         $expected = [
             [
@@ -171,14 +180,14 @@ public function it_can_convert_to_array()
     }
 
     /** @test */
-    public function it_can_convert_to_json()
+    public function it_can_convert_to_json(): void
     {
         $expected = '[]';
 
         static::assertSame($expected, json_encode($this->sitemap));
         static::assertSame($expected, $this->sitemap->toJson());
 
-        $this->sitemap->add($this->createUrlSample());
+        $this->sitemap->add(static::createUrlSample());
 
         $expected = json_encode($this->sitemap->toArray());
 
@@ -187,7 +196,7 @@ public function it_can_convert_to_json()
     }
 
     /** @test */
-    public function it_should_treats_urls_as_the_basic_collection_class()
+    public function it_should_treats_urls_as_the_basic_collection_class(): void
     {
         $this->sitemap = $this->createBlogSitemap();
 
@@ -197,7 +206,7 @@ public function it_should_treats_urls_as_the_basic_collection_class()
     }
 
     /** @test */
-    public function it_can_check_if_number_of_urls_is_exceeded()
+    public function it_can_check_if_number_of_urls_is_exceeded(): void
     {
         // Max is 500 for tests
 
@@ -218,9 +227,9 @@ public function it_can_check_if_number_of_urls_is_exceeded()
     }
 
     /** @test */
-    public function it_can_set_urls()
+    public function it_can_set_urls(): void
     {
-        $this->sitemap->add($this->createUrlSample());
+        $this->sitemap->add(static::createUrlSample());
 
         static::assertSame(1, $this->sitemap->count());
 
@@ -230,7 +239,7 @@ public function it_can_set_urls()
             ['loc' => 'http://example.com/contact'],
         ]);
 
-        $now = new \DateTime;
+        $now = new DateTime;
 
         $this->sitemap->setUrls($urls->transform(function (array $item) use ($now) {
             return Url::makeFromArray($item)->setLastMod($now);
@@ -238,7 +247,7 @@ public function it_can_set_urls()
 
         static::assertSame(3, $this->sitemap->count());
 
-        $formattedDate = $now->format(\DateTime::ATOM);
+        $formattedDate = $now->format(DateTime::ATOM);
 
         $expected = [
             [
@@ -266,9 +275,9 @@ public function it_can_set_urls()
     }
 
     /** @test */
-    public function it_can_add_many_urls_to_the_collection()
+    public function it_can_add_many_urls_to_the_collection(): void
     {
-        $this->sitemap->add($this->createUrlSample());
+        $this->sitemap->add(static::createUrlSample());
 
         static::assertSame(1, $this->sitemap->count());
 
@@ -278,7 +287,7 @@ public function it_can_add_many_urls_to_the_collection()
             ['loc' => 'http://example.com/contact'],
         ]);
 
-        $now = new \DateTime;
+        $now = new DateTime;
 
         $this->sitemap->addMany($urls->transform(function (array $item) use ($now) {
             return Url::makeFromArray($item)->setLastMod($now);
@@ -286,7 +295,7 @@ public function it_can_add_many_urls_to_the_collection()
 
         static::assertSame(4, $this->sitemap->count());
 
-        $formattedDate = $now->format(\DateTime::ATOM);
+        $formattedDate = $now->format(DateTime::ATOM);
 
         $expected = [
             [
@@ -329,7 +338,7 @@ public function it_can_add_many_urls_to_the_collection()
      *
      * @return \Arcanedev\LaravelSitemap\Entities\Url
      */
-    private function createUrlSample()
+    private static function createUrlSample(): Url
     {
         return Url::make('http://example.com')
             ->setChangeFreq(ChangeFrequency::ALWAYS)
diff --git a/tests/Entities/UrlTest.php b/tests/Entities/UrlTest.php
index a80d623..bd3dc64 100644
--- a/tests/Entities/UrlTest.php
+++ b/tests/Entities/UrlTest.php
@@ -1,8 +1,17 @@
-<?php namespace Arcanedev\LaravelSitemap\Tests\Entities;
+<?php
+
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap\Tests\Entities;
 
 use Arcanedev\LaravelSitemap\Contracts\Entities\ChangeFrequency;
 use Arcanedev\LaravelSitemap\Entities\Url;
+use Arcanedev\LaravelSitemap\Exceptions\SitemapException;
 use Arcanedev\LaravelSitemap\Tests\TestCase;
+use Carbon\Carbon;
+use Illuminate\Contracts\Support\{Arrayable, Jsonable};
+use DateTime;
+use JsonSerializable;
 
 /**
  * Class     UrlTest
@@ -45,13 +54,13 @@ protected function tearDown(): void
      */
 
     /** @test */
-    public function it_can_be_instantiated()
+    public function it_can_be_instantiated(): void
     {
         $expectations = [
-            \JsonSerializable::class,
-            \Illuminate\Contracts\Support\Arrayable::class,
-            \Illuminate\Contracts\Support\Jsonable::class,
-            \Arcanedev\LaravelSitemap\Entities\Url::class,
+            JsonSerializable::class,
+            Arrayable::class,
+            Jsonable::class,
+            Url::class,
         ];
 
         foreach ($expectations as $expected) {
@@ -60,12 +69,12 @@ public function it_can_be_instantiated()
     }
 
     /** @test */
-    public function it_can_also_instantiate_with_array()
+    public function it_can_also_instantiate_with_array(): void
     {
         $this->url = new Url([
             'title'      => 'Home page',
             'loc'        => 'http://example.com',
-            'lastmod'    => $now = new \DateTime,
+            'lastmod'    => $now = new DateTime,
             'changefreq' => 'hourly',
             'priority'   => 1.0,
         ]);
@@ -73,7 +82,7 @@ public function it_can_also_instantiate_with_array()
         $expected = [
             'title'      => 'Home page',
             'loc'        => 'http://example.com',
-            'lastmod'    => $now->format(\DateTime::ATOM),
+            'lastmod'    => $now->format(DateTime::ATOM),
             'changefreq' => 'hourly',
             'priority'   => 1.0,
         ];
@@ -82,10 +91,10 @@ public function it_can_also_instantiate_with_array()
     }
 
     /** @test */
-    public function it_can_make()
+    public function it_can_make(): void
     {
         static::assertInstanceOf(
-            \Arcanedev\LaravelSitemap\Entities\Url::class,
+            Url::class,
             $url = Url::make($loc = 'http://example.com')
         );
 
@@ -93,11 +102,11 @@ public function it_can_make()
     }
 
     /** @test */
-    public function it_can_make_from_array()
+    public function it_can_make_from_array(): void
     {
         $url = Url::makeFromArray(['loc' => 'http://example.com']); // With minimal attributes
 
-        static::assertInstanceOf(\Arcanedev\LaravelSitemap\Entities\Url::class, $url);
+        static::assertInstanceOf(Url::class, $url);
 
         $expected = [
             'loc'        => 'http://example.com',
@@ -109,7 +118,7 @@ public function it_can_make_from_array()
 
         static::assertSame($expected, $url->toArray());
 
-        $now = new \DateTime();
+        $now = new DateTime();
         $url = Url::makeFromArray([
             'title'      => 'Contact Page',
             'loc'        => 'http://example.com/contact',
@@ -121,7 +130,7 @@ public function it_can_make_from_array()
         $expected = [
             'title'      => 'Contact Page',
             'loc'        => 'http://example.com/contact',
-            'lastmod'    => $now->format(\DateTime::ATOM),
+            'lastmod'    => $now->format(DateTime::ATOM),
             'changefreq' => 'monthly',
             'priority'   => 0.5,
         ];
@@ -130,7 +139,7 @@ public function it_can_make_from_array()
     }
 
     /** @test */
-    public function it_can_get_and_set_location()
+    public function it_can_get_and_set_location(): void
     {
         static::assertSame('http://example.com', $this->url->getLoc());
 
@@ -140,22 +149,22 @@ public function it_can_get_and_set_location()
     }
 
     /** @test */
-    public function it_can_get_and_set_last_modification_date()
+    public function it_can_get_and_set_last_modification_date(): void
     {
-        static::assertInstanceOf(\DateTime::class, $this->url->getLastMod());
+        static::assertInstanceOf(DateTime::class, $this->url->getLastMod());
         static::assertSame(date('Y-m-d H:i'), $this->url->getLastMod()->format('Y-m-d H:i'));
 
         $this->url->setLastMod($date = '2017-01-01 00:00:00'); // String date
 
         static::assertSame($date, $this->url->getLastMod()->format('Y-m-d H:i:s'));
 
-        $this->url->setLastMod($date = new \DateTime);
+        $this->url->setLastMod($date = new DateTime);
 
         static::assertSame($date, $this->url->getLastMod());
     }
 
     /** @test */
-    public function it_can_get_and_set_change_freq()
+    public function it_can_get_and_set_change_freq(): void
     {
         static::assertSame(ChangeFrequency::DAILY, $this->url->getChangeFreq());
 
@@ -165,7 +174,7 @@ public function it_can_get_and_set_change_freq()
     }
 
     /** @test */
-    public function it_can_get_and_set_priority()
+    public function it_can_get_and_set_priority(): void
     {
         static::assertSame(0.8, $this->url->getPriority());
 
@@ -175,7 +184,7 @@ public function it_can_get_and_set_priority()
     }
 
     /** @test */
-    public function it_can_get_and_set_title()
+    public function it_can_get_and_set_title(): void
     {
         static::assertNull($this->url->getTitle());
 
@@ -185,7 +194,7 @@ public function it_can_get_and_set_title()
     }
 
     /** @test */
-    public function it_can_convert_to_array()
+    public function it_can_convert_to_array(): void
     {
         $this->url->setLastMod('2017-01-01 00:00:00');
 
@@ -201,7 +210,7 @@ public function it_can_convert_to_array()
     }
 
     /** @test */
-    public function it_can_convert_to_json()
+    public function it_can_convert_to_json(): void
     {
         $this->url->setLastMod('2017-01-01 00:00:00');
 
@@ -212,7 +221,7 @@ public function it_can_convert_to_json()
     }
 
     /** @test */
-    public function it_must_escape_the_url_location()
+    public function it_must_escape_the_url_location(): void
     {
         $url = Url::make('http://www.example.com/ümlat.php&q=name')
             ->setTitle('<hello type="shout">world</hello>');
@@ -222,47 +231,47 @@ public function it_must_escape_the_url_location()
     }
 
     /** @test */
-    public function it_must_fail_if_loc_is_invalid_1()
+    public function it_must_fail_if_loc_is_invalid_1(): void
     {
-        $this->expectException(\Arcanedev\LaravelSitemap\Exceptions\SitemapException::class);
+        $this->expectException(SitemapException::class);
         $this->expectExceptionMessage('The [loc] attribute is required and must be string value.');
 
         Url::make(null);
     }
 
     /** @test */
-    public function it_must_fail_if_loc_is_invalid_2()
+    public function it_must_fail_if_loc_is_invalid_2(): void
     {
-        $this->expectException(\Arcanedev\LaravelSitemap\Exceptions\SitemapException::class);
+        $this->expectException(SitemapException::class);
         $this->expectExceptionMessage('The [loc] attribute is required and must be string value.');
 
         Url::make(true);
     }
 
     /** @test */
-    public function it_must_fail_if_priority_is_invalid_1()
+    public function it_must_fail_if_priority_is_invalid_1(): void
     {
-        $this->expectException(\Arcanedev\LaravelSitemap\Exceptions\SitemapException::class);
+        $this->expectException(SitemapException::class);
         $this->expectExceptionMessage('The [priority] value must be numeric.');
 
         Url::make($this->baseUrl)->setPriority('foo');
     }
 
     /** @test */
-    public function it_must_fail_if_priority_is_invalid_2()
+    public function it_must_fail_if_priority_is_invalid_2(): void
     {
-        $this->expectException(\Arcanedev\LaravelSitemap\Exceptions\SitemapException::class);
+        $this->expectException(SitemapException::class);
         $this->expectExceptionMessage('The [priority] value must be between `0.0` and `1.0`, `2` was given.');
 
         Url::make($this->baseUrl)->setPriority('2.0');
     }
 
     /** @test */
-    public function it_can_manipulate_extra_attributes()
+    public function it_can_manipulate_extra_attributes(): void
     {
         $url = Url::makeFromArray([
             'loc'        => 'http://example.com',
-            'lastmod'    => \Carbon\Carbon::create(2017, 01, 01, 00, 00, 00),
+            'lastmod'    => Carbon::create(2017, 01, 01, 00, 00, 00),
             'changefreq' => ChangeFrequency::DAILY,
             'priority'   => 1.0,
             'title'      => 'Hello world',
diff --git a/tests/LaravelSitemapServiceProviderTest.php b/tests/LaravelSitemapServiceProviderTest.php
index 37599fe..d3f075c 100644
--- a/tests/LaravelSitemapServiceProviderTest.php
+++ b/tests/LaravelSitemapServiceProviderTest.php
@@ -1,4 +1,10 @@
-<?php namespace Arcanedev\LaravelSitemap\Tests;
+<?php
+
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap\Tests;
+
+use Arcanedev\LaravelSitemap\LaravelSitemapServiceProvider;
 
 /**
  * Class     LaravelSitemapServiceProviderTest
@@ -25,7 +31,7 @@ protected function setUp(): void
     {
         parent::setUp();
 
-        $this->provider = $this->app->getProvider(\Arcanedev\LaravelSitemap\LaravelSitemapServiceProvider::class);
+        $this->provider = $this->app->getProvider(LaravelSitemapServiceProvider::class);
     }
 
     protected function tearDown(): void
@@ -41,14 +47,14 @@ protected function tearDown(): void
      */
 
     /** @test */
-    public function it_can_be_instantiated()
+    public function it_can_be_instantiated(): void
     {
         $expectations = [
             \Illuminate\Support\ServiceProvider::class,
             \Illuminate\Contracts\Support\DeferrableProvider::class,
             \Arcanedev\Support\Providers\ServiceProvider::class,
             \Arcanedev\Support\Providers\PackageServiceProvider::class,
-            \Arcanedev\LaravelSitemap\LaravelSitemapServiceProvider::class,
+            LaravelSitemapServiceProvider::class,
         ];
 
         foreach ($expectations as $expected) {
@@ -57,7 +63,7 @@ public function it_can_be_instantiated()
     }
 
     /** @test */
-    public function it_can_provides()
+    public function it_can_provides(): void
     {
         $expected = [
             \Arcanedev\LaravelSitemap\Contracts\SitemapManager::class,
diff --git a/tests/SitemapManagerTest.php b/tests/SitemapManagerTest.php
index cee7880..dbeb229 100644
--- a/tests/SitemapManagerTest.php
+++ b/tests/SitemapManagerTest.php
@@ -1,7 +1,12 @@
-<?php namespace Arcanedev\LaravelSitemap\Tests;
+<?php
 
-use Arcanedev\LaravelSitemap\Entities\Sitemap;
-use Arcanedev\LaravelSitemap\Entities\Url;
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap\Tests;
+
+use Arcanedev\LaravelSitemap\Contracts\SitemapManager;
+use Illuminate\Http\Response;
+use Arcanedev\LaravelSitemap\Entities\{Sitemap, Url};
 use Spatie\Snapshots\MatchesSnapshots;
 
 /**
@@ -36,7 +41,7 @@ protected function setUp(): void
     {
         parent::setUp();
 
-        $this->manager = $this->app->make(\Arcanedev\LaravelSitemap\Contracts\SitemapManager::class);
+        $this->manager = $this->app->make(SitemapManager::class);
     }
 
     protected function tearDown(): void
@@ -52,10 +57,10 @@ protected function tearDown(): void
      */
 
     /** @test */
-    public function it_can_be_instantiated()
+    public function it_can_be_instantiated(): void
     {
         $expectations = [
-            \Arcanedev\LaravelSitemap\Contracts\SitemapManager::class,
+            SitemapManager::class,
             \Arcanedev\LaravelSitemap\SitemapManager::class,
         ];
 
@@ -65,14 +70,14 @@ public function it_can_be_instantiated()
     }
 
     /** @test */
-    public function it_should_return_empty_sitemaps_collection_on_creation()
+    public function it_should_return_empty_sitemaps_collection_on_creation(): void
     {
         static::assertCount(0, $this->manager->all());
         static::assertSame(0, $this->manager->count());
     }
 
     /** @test */
-    public function it_can_add_a_sitemap_to_collection()
+    public function it_can_add_a_sitemap_to_collection(): void
     {
         $this->manager->add('pages', $sitemap = new Sitemap);
 
@@ -83,7 +88,7 @@ public function it_can_add_a_sitemap_to_collection()
     }
 
     /** @test */
-    public function it_can_get_a_sitemap_by_its_name()
+    public function it_can_get_a_sitemap_by_its_name(): void
     {
         $this->manager->add('blog', $sitemap = new Sitemap);
 
@@ -92,11 +97,11 @@ public function it_can_get_a_sitemap_by_its_name()
 
         $sitemap = $this->manager->get('blog');
 
-        static::assertInstanceOf(\Arcanedev\LaravelSitemap\Entities\Sitemap::class, $sitemap);
+        static::assertInstanceOf(Sitemap::class, $sitemap);
     }
 
     /** @test */
-    public function it_can_create_and_add_a_sitemap_to_collection()
+    public function it_can_create_and_add_a_sitemap_to_collection(): void
     {
         $this->manager->create('pages', function (Sitemap $sitemap) {
             $sitemap->add(Url::make('http://example.com'));
@@ -111,7 +116,7 @@ public function it_can_create_and_add_a_sitemap_to_collection()
     }
 
     /** @test */
-    public function it_can_forget_sitemaps_from_collection()
+    public function it_can_forget_sitemaps_from_collection(): void
     {
         $this->populatedManager();
 
@@ -123,7 +128,7 @@ public function it_can_forget_sitemaps_from_collection()
     }
 
     /** @test */
-    public function it_can_convert_to_array()
+    public function it_can_convert_to_array(): void
     {
         static::assertSame([], $this->manager->toArray());
 
@@ -141,7 +146,7 @@ public function it_can_convert_to_array()
     }
 
     /** @test */
-    public function it_can_convert_to_json()
+    public function it_can_convert_to_json(): void
     {
         $expected = '[]';
 
@@ -158,7 +163,7 @@ public function it_can_convert_to_json()
 
 
     /** @test */
-    public function it_can_render_sitemaps()
+    public function it_can_render_sitemaps(): void
     {
         $this->populatedManager();
 
@@ -170,13 +175,13 @@ public function it_can_render_sitemaps()
     }
 
     /** @test */
-    public function it_should_return_null_when_rendering_an_empty_manager()
+    public function it_should_return_null_when_rendering_an_empty_manager(): void
     {
         static::assertNull($this->manager->render());
     }
 
     /** @test */
-    public function it_can_save_sitemap_index()
+    public function it_can_save_sitemap_index(): void
     {
         $directory = __DIR__.'/__temp__';
         $this->manager->save($path = "$directory/sitemap.xml");
@@ -194,7 +199,7 @@ public function it_can_save_sitemap_index()
     }
 
     /** @test */
-    public function it_can_save_sitemaps()
+    public function it_can_save_sitemaps(): void
     {
         $directory = __DIR__.'/__temp__';
 
@@ -213,7 +218,7 @@ public function it_can_save_sitemaps()
     }
 
     /** @test */
-    public function it_can_save_the_single_sitemap_instead_of_index()
+    public function it_can_save_the_single_sitemap_instead_of_index(): void
     {
         $directory = __DIR__.'/__temp__';
         $path = "$directory/sitemap.xml";
@@ -229,7 +234,7 @@ public function it_can_save_the_single_sitemap_instead_of_index()
     }
 
     /** @test */
-    public function it_can_switch_sitemap_format_to_txt()
+    public function it_can_switch_sitemap_format_to_txt(): void
     {
         $this->manager->format('txt');
 
@@ -245,7 +250,7 @@ public function it_can_switch_sitemap_format_to_txt()
     }
 
     /** @test */
-    public function it_can_switch_sitemap_format_to_rss()
+    public function it_can_switch_sitemap_format_to_rss(): void
     {
         $this->manager->format('rss');
 
@@ -261,7 +266,7 @@ public function it_can_switch_sitemap_format_to_rss()
     }
 
     /** @test */
-    public function it_must_return_null_if_format_is_invalid()
+    public function it_must_return_null_if_format_is_invalid(): void
     {
         $this->populatedManager();
 
@@ -273,7 +278,7 @@ public function it_must_return_null_if_format_is_invalid()
     }
 
     /** @test */
-    public function it_can_chunk_a_huge_sitemap_on_render()
+    public function it_can_chunk_a_huge_sitemap_on_render(): void
     {
         $this->manager->add('blog', $this->createBlogSitemap(499));
 
@@ -291,7 +296,7 @@ public function it_can_chunk_a_huge_sitemap_on_render()
     }
 
     /** @test */
-    public function it_can_chunk_a_huge_sitemap_on_save()
+    public function it_can_chunk_a_huge_sitemap_on_save(): void
     {
         $this->manager->add('blog', $this->createBlogSitemap(499));
 
@@ -316,13 +321,13 @@ public function it_can_chunk_a_huge_sitemap_on_save()
     }
 
     /** @test */
-    public function it_can_respond_with_http_response()
+    public function it_can_respond_with_http_response(): void
     {
         $response = $this->manager->respond();
 
-        static::assertInstanceOf(\Illuminate\Http\Response::class, $response);
+        static::assertInstanceOf(Response::class, $response);
 
-        static::assertSame(200, $response->getStatusCode());
+        static::assertSame(Response::HTTP_OK, $response->getStatusCode());
         static::assertSame('', $response->getContent());
         static::assertSame('application/xml', $response->headers->get('content-type'));
 
@@ -330,19 +335,19 @@ public function it_can_respond_with_http_response()
 
         $response = $this->manager->respond();
 
-        static::assertSame(200, $response->getStatusCode());
+        static::assertSame(Response::HTTP_OK, $response->getStatusCode());
         static::assertMatchesXmlSnapshot($response->getContent());
         static::assertSame('application/xml', $response->headers->get('content-type'));
 
         $response = $this->manager->format('txt')->respond();
 
-        static::assertSame(200, $response->getStatusCode());
+        static::assertSame(Response::HTTP_OK, $response->getStatusCode());
         static::assertMatchesSnapshot($response->getContent());
         static::assertSame('text/plain', $response->headers->get('content-type'));
 
         $response = $this->manager->format('rss')->respond('blog');
 
-        static::assertSame(200, $response->getStatusCode());
+        static::assertSame(Response::HTTP_OK, $response->getStatusCode());
         static::assertMatchesSnapshot($response->getContent());
         static::assertSame('application/rss+xml', $response->headers->get('content-type'));
     }
@@ -355,7 +360,7 @@ public function it_can_respond_with_http_response()
     /**
      * Populate the manager with sitemaps.
      */
-    private function populatedManager()
+    private function populatedManager(): void
     {
         $this->manager->add('pages', $this->createPagesSitemap());
         $this->manager->add('blog', $this->createBlogSitemap());
diff --git a/tests/TestCase.php b/tests/TestCase.php
index 78d3558..d328a4d 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -1,8 +1,11 @@
-<?php namespace Arcanedev\LaravelSitemap\Tests;
+<?php
+
+declare(strict_types=1);
+
+namespace Arcanedev\LaravelSitemap\Tests;
 
 use Arcanedev\LaravelSitemap\Contracts\Entities\ChangeFrequency;
-use Arcanedev\LaravelSitemap\Entities\Sitemap;
-use Arcanedev\LaravelSitemap\Entities\Url;
+use Arcanedev\LaravelSitemap\Entities\{Sitemap, Url};
 use Orchestra\Testbench\TestCase as BaseTestCase;
 
 /**
@@ -25,7 +28,7 @@ abstract class TestCase extends BaseTestCase
      *
      * @return array
      */
-    protected function getPackageProviders($app)
+    protected function getPackageProviders($app): array
     {
         return [
             \Arcanedev\LaravelSitemap\LaravelSitemapServiceProvider::class,
@@ -37,7 +40,7 @@ protected function getPackageProviders($app)
      *
      * @param  \Illuminate\Foundation\Application   $app
      */
-    protected function getEnvironmentSetUp($app)
+    protected function getEnvironmentSetUp($app): void
     {
         $app['config']->set('sitemap.urls-max-size', 100);
     }
@@ -54,7 +57,7 @@ protected function getEnvironmentSetUp($app)
      * @param  array   $array
      * @param  string  $message
      */
-    public static function assertArrayHasKeys(array $keys, $array, $message = '')
+    public static function assertArrayHasKeys(array $keys, $array, $message = ''): void
     {
         foreach ($keys as $key) {
             static::assertArrayHasKey($key, $array, $message);
@@ -67,9 +70,11 @@ public static function assertArrayHasKeys(array $keys, $array, $message = '')
      */
 
     /**
+     * Create 'pages' sitemap.
+     *
      * @return \Arcanedev\LaravelSitemap\Entities\Sitemap
      */
-    protected function createPagesSitemap()
+    protected function createPagesSitemap(): Sitemap
     {
         return tap(new Sitemap, function (Sitemap $sitemap) {
             $baseUrl = 'http://example.com';
@@ -83,11 +88,13 @@ protected function createPagesSitemap()
     }
 
     /**
+     * Create `blog` sitemap.
+     *
      * @param  int  $times
      *
      * @return \Arcanedev\LaravelSitemap\Entities\Sitemap
      */
-    protected function createBlogSitemap($times = 10)
+    protected function createBlogSitemap($times = 10): Sitemap
     {
         return tap(new Sitemap, function (Sitemap $sitemap) use ($times) {
             $baseUrl = 'http://example.com';