diff --git a/.coveralls.yml b/.coveralls.yml
new file mode 100644
index 0000000..a8172fe
--- /dev/null
+++ b/.coveralls.yml
@@ -0,0 +1 @@
+json_path: coveralls-upload.json
diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 0000000..9e4c2ee
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,8 @@
+version: 2
+updates:
+- package-ecosystem: composer
+  directory: "/"
+  schedule:
+    interval: monthly
+  open-pull-requests-limit: 10
+  versioning-strategy: increase
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
new file mode 100644
index 0000000..2934da2
--- /dev/null
+++ b/.github/workflows/tests.yml
@@ -0,0 +1,49 @@
+name: Tests
+
+on: [push, pull_request]
+
+jobs:
+    tests:
+        name: Tests PHP ${{ matrix.php }}
+        runs-on: ubuntu-latest
+        continue-on-error: ${{ matrix.experimental }}
+        strategy:
+            fail-fast: false
+            matrix:
+                php: [7.4, 8.0, 8.1]
+                experimental: [false]
+                include:
+                    - php: 8.1
+                      analysis: true
+
+        steps:
+            - name: Checkout
+              uses: actions/checkout@v2
+
+            - name: Set up PHP ${{ matrix.php }}
+              uses: shivammathur/setup-php@v2
+              with:
+                  php-version: ${{ matrix.php }}
+                  coverage: xdebug
+
+            - name: Install dependencies with Composer
+              uses: ramsey/composer-install@v2
+
+            - name: Coding standards
+              if: matrix.analysis
+              run: vendor/bin/phpcs
+
+            - name: Static analysis
+              if: matrix.analysis
+              run: vendor/bin/phpstan
+
+            - name: Tests
+              run: vendor/bin/phpunit --coverage-clover clover.xml
+
+            - name: Upload coverage results to Coveralls
+              if: matrix.analysis
+              env:
+                  COVERALLS_REPO_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+              run: |
+                  composer require php-coveralls/php-coveralls -n -W
+                  vendor/bin/php-coveralls --coverage_clover=clover.xml -v
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..2ebad0b
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,8 @@
+.idea/
+.vscode/
+/coverage/
+/vendor/
+/logs/*
+!/logs/README.md
+.phpunit.result.cache
+.DS_Store
\ No newline at end of file
diff --git a/.htaccess b/.htaccess
new file mode 100644
index 0000000..c7552bf
--- /dev/null
+++ b/.htaccess
@@ -0,0 +1,19 @@
+Options All -Indexes
+
+<Files .htaccess>
+order allow,deny
+deny from all
+</Files>
+
+<IfModule mod_rewrite.c>
+  # Redirect to the public folder
+  RewriteEngine On
+  # RewriteBase /
+  RewriteRule ^$ public/ [L]
+  RewriteRule (.*) public/$1 [L]
+
+  # Redirect to HTTPS
+  # RewriteEngine On
+  # RewriteCond %{HTTPS} off
+  # RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
+</IfModule>
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..c7878cb
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,14 @@
+# How to Contribute
+
+## Pull Requests
+
+1. Fork the Slim Skeleton repository
+2. Create a new branch for each feature or improvement
+3. Send a pull request from each feature branch to the **4.x** branch
+
+It is very important to separate new features or improvements into separate feature branches, and to send a
+pull request for each branch. This allows us to review and pull in new features or improvements individually.
+
+## Style Guide
+
+All pull requests must adhere to the [PSR-12 standard](https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-12-extended-coding-style-guide.md).
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..f769efc
--- /dev/null
+++ b/README.md
@@ -0,0 +1,66 @@
+# MTEX Mock API
+
+Simple REST API providing sample JSON data for testing and prototyping.
+
+## Installation
+
+```bash
+composer install
+```
+
+## Local Development
+
+```bash
+php -S localhost:8000 -t public
+```
+
+Visit `http://localhost:8000` to see the API documentation.
+
+## Endpoints
+
+### Documentation
+
+- `GET /` - API documentation
+
+### Users
+
+- `GET /users` - List all users
+- `GET /users/{id}` - Get user by ID
+
+### Posts
+
+- `GET /posts` - List all posts
+- `GET /posts/{id}` - Get post by ID
+
+### Products
+
+- `GET /products` - List all products
+- `GET /products/{id}` - Get product by ID
+
+## Example Requests
+
+```bash
+curl https://mock.mtex.dev/users
+curl https://mock.mtex.dev/users/1
+curl https://mock.mtex.dev/posts
+curl https://mock.mtex.dev/products/2
+```
+
+## Features
+
+- [x] RESTful API design
+- [x] JSON responses
+- [x] CORS enabled
+- [x] Error handling
+- [x] Self-documenting
+- [x] No database required
+
+## Tech Stack
+
+- PHP 8.1+
+- Slim Framework 4
+- PSR-7 HTTP Messages
+
+## License
+
+MIT
\ No newline at end of file
diff --git a/app/dependencies.php b/app/dependencies.php
new file mode 100644
index 0000000..fd3f066
--- /dev/null
+++ b/app/dependencies.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Application\Settings\SettingsInterface;
+use DI\ContainerBuilder;
+use Monolog\Handler\StreamHandler;
+use Monolog\Logger;
+use Monolog\Processor\UidProcessor;
+use Psr\Container\ContainerInterface;
+use Psr\Log\LoggerInterface;
+
+return function (ContainerBuilder $containerBuilder) {
+    $containerBuilder->addDefinitions([
+        LoggerInterface::class => function (ContainerInterface $c) {
+            $settings = $c->get(SettingsInterface::class);
+
+            $loggerSettings = $settings->get('logger');
+            $logger = new Logger($loggerSettings['name']);
+
+            $processor = new UidProcessor();
+            $logger->pushProcessor($processor);
+
+            $handler = new StreamHandler($loggerSettings['path'], $loggerSettings['level']);
+            $logger->pushHandler($handler);
+
+            return $logger;
+        },
+    ]);
+};
diff --git a/app/middleware.php b/app/middleware.php
new file mode 100644
index 0000000..a3f6cf9
--- /dev/null
+++ b/app/middleware.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Application\Middleware\SessionMiddleware;
+use Slim\App;
+
+return function (App $app) {
+    $app->add(SessionMiddleware::class);
+};
diff --git a/app/repositories.php b/app/repositories.php
new file mode 100644
index 0000000..15f20f3
--- /dev/null
+++ b/app/repositories.php
@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Domain\User\UserRepository;
+use App\Infrastructure\Persistence\User\InMemoryUserRepository;
+use DI\ContainerBuilder;
+
+return function (ContainerBuilder $containerBuilder) {
+    // Here we map our UserRepository interface to its in memory implementation
+    $containerBuilder->addDefinitions([
+        UserRepository::class => \DI\autowire(InMemoryUserRepository::class),
+    ]);
+};
diff --git a/app/routes.php b/app/routes.php
new file mode 100644
index 0000000..17e4b82
--- /dev/null
+++ b/app/routes.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Application\Actions\User\ListUsersAction;
+use App\Application\Actions\User\ViewUserAction;
+use Psr\Http\Message\ResponseInterface as Response;
+use Psr\Http\Message\ServerRequestInterface as Request;
+use Slim\App;
+use Slim\Interfaces\RouteCollectorProxyInterface as Group;
+
+return function (App $app) {
+    $app->options('/{routes:.*}', function (Request $request, Response $response) {
+        // CORS Pre-Flight OPTIONS Request Handler
+        return $response;
+    });
+
+    $app->get('/', function (Request $request, Response $response) {
+        $response->getBody()->write('Hello world!');
+        return $response;
+    });
+
+    $app->group('/users', function (Group $group) {
+        $group->get('', ListUsersAction::class);
+        $group->get('/{id}', ViewUserAction::class);
+    });
+};
diff --git a/app/settings.php b/app/settings.php
new file mode 100644
index 0000000..79392bd
--- /dev/null
+++ b/app/settings.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Application\Settings\Settings;
+use App\Application\Settings\SettingsInterface;
+use DI\ContainerBuilder;
+use Monolog\Logger;
+
+return function (ContainerBuilder $containerBuilder) {
+
+    // Global Settings Object
+    $containerBuilder->addDefinitions([
+        SettingsInterface::class => function () {
+            return new Settings([
+                'displayErrorDetails' => true, // Should be set to false in production
+                'logError'            => false,
+                'logErrorDetails'     => false,
+                'logger' => [
+                    'name' => 'slim-app',
+                    'path' => isset($_ENV['docker']) ? 'php://stdout' : __DIR__ . '/../logs/app.log',
+                    'level' => Logger::DEBUG,
+                ],
+            ]);
+        }
+    ]);
+};
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..d32875e
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,15 @@
+{
+  "name": "mtex/mock-api",
+  "description": "Simple REST API providing sample JSON data",
+  "type": "project",
+  "require": {
+    "php": "^8.1",
+    "slim/slim": "^4.12",
+    "slim/psr7": "^1.6"
+  },
+  "autoload": {
+    "psr-4": {
+      "App\\": "src/"
+    }
+  }
+}
\ No newline at end of file
diff --git a/composer.lock b/composer.lock
new file mode 100644
index 0000000..b62b333
--- /dev/null
+++ b/composer.lock
@@ -0,0 +1,690 @@
+{
+    "_readme": [
+        "This file locks the dependencies of your project to a known state",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
+        "This file is @generated automatically"
+    ],
+    "content-hash": "e6111b07c655e23e9706a7e73e61a3b4",
+    "packages": [
+        {
+            "name": "fig/http-message-util",
+            "version": "1.1.5",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/http-message-util.git",
+                "reference": "9d94dc0154230ac39e5bf89398b324a86f63f765"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/http-message-util/zipball/9d94dc0154230ac39e5bf89398b324a86f63f765",
+                "reference": "9d94dc0154230ac39e5bf89398b324a86f63f765",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.3 || ^7.0 || ^8.0"
+            },
+            "suggest": {
+                "psr/http-message": "The package containing the PSR-7 interfaces"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.1.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Fig\\Http\\Message\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "https://www.php-fig.org/"
+                }
+            ],
+            "description": "Utility classes and constants for use with PSR-7 (psr/http-message)",
+            "keywords": [
+                "http",
+                "http-message",
+                "psr",
+                "psr-7",
+                "request",
+                "response"
+            ],
+            "support": {
+                "issues": "https://github.com/php-fig/http-message-util/issues",
+                "source": "https://github.com/php-fig/http-message-util/tree/1.1.5"
+            },
+            "time": "2020-11-24T22:02:12+00:00"
+        },
+        {
+            "name": "nikic/fast-route",
+            "version": "v1.3.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nikic/FastRoute.git",
+                "reference": "181d480e08d9476e61381e04a71b34dc0432e812"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nikic/FastRoute/zipball/181d480e08d9476e61381e04a71b34dc0432e812",
+                "reference": "181d480e08d9476e61381e04a71b34dc0432e812",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.4.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^4.8.35|~5.7"
+            },
+            "type": "library",
+            "autoload": {
+                "files": [
+                    "src/functions.php"
+                ],
+                "psr-4": {
+                    "FastRoute\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Nikita Popov",
+                    "email": "nikic@php.net"
+                }
+            ],
+            "description": "Fast request router for PHP",
+            "keywords": [
+                "router",
+                "routing"
+            ],
+            "support": {
+                "issues": "https://github.com/nikic/FastRoute/issues",
+                "source": "https://github.com/nikic/FastRoute/tree/master"
+            },
+            "time": "2018-02-13T20:26:39+00:00"
+        },
+        {
+            "name": "psr/container",
+            "version": "2.0.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/container.git",
+                "reference": "c71ecc56dfe541dbd90c5360474fbc405f8d5963"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/container/zipball/c71ecc56dfe541dbd90c5360474fbc405f8d5963",
+                "reference": "c71ecc56dfe541dbd90c5360474fbc405f8d5963",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.4.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psr\\Container\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "https://www.php-fig.org/"
+                }
+            ],
+            "description": "Common Container Interface (PHP FIG PSR-11)",
+            "homepage": "https://github.com/php-fig/container",
+            "keywords": [
+                "PSR-11",
+                "container",
+                "container-interface",
+                "container-interop",
+                "psr"
+            ],
+            "support": {
+                "issues": "https://github.com/php-fig/container/issues",
+                "source": "https://github.com/php-fig/container/tree/2.0.2"
+            },
+            "time": "2021-11-05T16:47:00+00:00"
+        },
+        {
+            "name": "psr/http-factory",
+            "version": "1.1.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/http-factory.git",
+                "reference": "2b4765fddfe3b508ac62f829e852b1501d3f6e8a"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/http-factory/zipball/2b4765fddfe3b508ac62f829e852b1501d3f6e8a",
+                "reference": "2b4765fddfe3b508ac62f829e852b1501d3f6e8a",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.1",
+                "psr/http-message": "^1.0 || ^2.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psr\\Http\\Message\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "https://www.php-fig.org/"
+                }
+            ],
+            "description": "PSR-17: Common interfaces for PSR-7 HTTP message factories",
+            "keywords": [
+                "factory",
+                "http",
+                "message",
+                "psr",
+                "psr-17",
+                "psr-7",
+                "request",
+                "response"
+            ],
+            "support": {
+                "source": "https://github.com/php-fig/http-factory"
+            },
+            "time": "2024-04-15T12:06:14+00:00"
+        },
+        {
+            "name": "psr/http-message",
+            "version": "2.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/http-message.git",
+                "reference": "402d35bcb92c70c026d1a6a9883f06b2ead23d71"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/http-message/zipball/402d35bcb92c70c026d1a6a9883f06b2ead23d71",
+                "reference": "402d35bcb92c70c026d1a6a9883f06b2ead23d71",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.2 || ^8.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psr\\Http\\Message\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "https://www.php-fig.org/"
+                }
+            ],
+            "description": "Common interface for HTTP messages",
+            "homepage": "https://github.com/php-fig/http-message",
+            "keywords": [
+                "http",
+                "http-message",
+                "psr",
+                "psr-7",
+                "request",
+                "response"
+            ],
+            "support": {
+                "source": "https://github.com/php-fig/http-message/tree/2.0"
+            },
+            "time": "2023-04-04T09:54:51+00:00"
+        },
+        {
+            "name": "psr/http-server-handler",
+            "version": "1.0.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/http-server-handler.git",
+                "reference": "84c4fb66179be4caaf8e97bd239203245302e7d4"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/http-server-handler/zipball/84c4fb66179be4caaf8e97bd239203245302e7d4",
+                "reference": "84c4fb66179be4caaf8e97bd239203245302e7d4",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.0",
+                "psr/http-message": "^1.0 || ^2.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psr\\Http\\Server\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "https://www.php-fig.org/"
+                }
+            ],
+            "description": "Common interface for HTTP server-side request handler",
+            "keywords": [
+                "handler",
+                "http",
+                "http-interop",
+                "psr",
+                "psr-15",
+                "psr-7",
+                "request",
+                "response",
+                "server"
+            ],
+            "support": {
+                "source": "https://github.com/php-fig/http-server-handler/tree/1.0.2"
+            },
+            "time": "2023-04-10T20:06:20+00:00"
+        },
+        {
+            "name": "psr/http-server-middleware",
+            "version": "1.0.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/http-server-middleware.git",
+                "reference": "c1481f747daaa6a0782775cd6a8c26a1bf4a3829"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/http-server-middleware/zipball/c1481f747daaa6a0782775cd6a8c26a1bf4a3829",
+                "reference": "c1481f747daaa6a0782775cd6a8c26a1bf4a3829",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.0",
+                "psr/http-message": "^1.0 || ^2.0",
+                "psr/http-server-handler": "^1.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psr\\Http\\Server\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "https://www.php-fig.org/"
+                }
+            ],
+            "description": "Common interface for HTTP server-side middleware",
+            "keywords": [
+                "http",
+                "http-interop",
+                "middleware",
+                "psr",
+                "psr-15",
+                "psr-7",
+                "request",
+                "response"
+            ],
+            "support": {
+                "issues": "https://github.com/php-fig/http-server-middleware/issues",
+                "source": "https://github.com/php-fig/http-server-middleware/tree/1.0.2"
+            },
+            "time": "2023-04-11T06:14:47+00:00"
+        },
+        {
+            "name": "psr/log",
+            "version": "3.0.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/log.git",
+                "reference": "f16e1d5863e37f8d8c2a01719f5b34baa2b714d3"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/log/zipball/f16e1d5863e37f8d8c2a01719f5b34baa2b714d3",
+                "reference": "f16e1d5863e37f8d8c2a01719f5b34baa2b714d3",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=8.0.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psr\\Log\\": "src"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "https://www.php-fig.org/"
+                }
+            ],
+            "description": "Common interface for logging libraries",
+            "homepage": "https://github.com/php-fig/log",
+            "keywords": [
+                "log",
+                "psr",
+                "psr-3"
+            ],
+            "support": {
+                "source": "https://github.com/php-fig/log/tree/3.0.2"
+            },
+            "time": "2024-09-11T13:17:53+00:00"
+        },
+        {
+            "name": "ralouphie/getallheaders",
+            "version": "3.0.3",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/ralouphie/getallheaders.git",
+                "reference": "120b605dfeb996808c31b6477290a714d356e822"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/ralouphie/getallheaders/zipball/120b605dfeb996808c31b6477290a714d356e822",
+                "reference": "120b605dfeb996808c31b6477290a714d356e822",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.6"
+            },
+            "require-dev": {
+                "php-coveralls/php-coveralls": "^2.1",
+                "phpunit/phpunit": "^5 || ^6.5"
+            },
+            "type": "library",
+            "autoload": {
+                "files": [
+                    "src/getallheaders.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Ralph Khattar",
+                    "email": "ralph.khattar@gmail.com"
+                }
+            ],
+            "description": "A polyfill for getallheaders.",
+            "support": {
+                "issues": "https://github.com/ralouphie/getallheaders/issues",
+                "source": "https://github.com/ralouphie/getallheaders/tree/develop"
+            },
+            "time": "2019-03-08T08:55:37+00:00"
+        },
+        {
+            "name": "slim/psr7",
+            "version": "1.8.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/slimphp/Slim-Psr7.git",
+                "reference": "76e7e3b1cdfd583e9035c4c966c08e01e45ce959"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/slimphp/Slim-Psr7/zipball/76e7e3b1cdfd583e9035c4c966c08e01e45ce959",
+                "reference": "76e7e3b1cdfd583e9035c4c966c08e01e45ce959",
+                "shasum": ""
+            },
+            "require": {
+                "fig/http-message-util": "^1.1.5",
+                "php": "^8.0",
+                "psr/http-factory": "^1.1",
+                "psr/http-message": "^1.0 || ^2.0",
+                "ralouphie/getallheaders": "^3.0"
+            },
+            "provide": {
+                "psr/http-factory-implementation": "^1.0",
+                "psr/http-message-implementation": "^1.0 || ^2.0"
+            },
+            "require-dev": {
+                "adriansuter/php-autoload-override": "^1.5|| ^2.0",
+                "ext-json": "*",
+                "http-interop/http-factory-tests": "^1.0 || ^2.0",
+                "php-http/psr7-integration-tests": "^1.5",
+                "phpstan/phpstan": "^2.1",
+                "phpunit/phpunit": "^9.6 || ^10",
+                "squizlabs/php_codesniffer": "^3.13"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Slim\\Psr7\\": "src"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Josh Lockhart",
+                    "email": "hello@joshlockhart.com",
+                    "homepage": "https://joshlockhart.com"
+                },
+                {
+                    "name": "Andrew Smith",
+                    "email": "a.smith@silentworks.co.uk",
+                    "homepage": "https://silentworks.co.uk"
+                },
+                {
+                    "name": "Rob Allen",
+                    "email": "rob@akrabat.com",
+                    "homepage": "https://akrabat.com"
+                },
+                {
+                    "name": "Pierre Berube",
+                    "email": "pierre@lgse.com",
+                    "homepage": "https://www.lgse.com"
+                }
+            ],
+            "description": "Strict PSR-7 implementation",
+            "homepage": "https://www.slimframework.com",
+            "keywords": [
+                "http",
+                "psr-7",
+                "psr7"
+            ],
+            "support": {
+                "issues": "https://github.com/slimphp/Slim-Psr7/issues",
+                "source": "https://github.com/slimphp/Slim-Psr7/tree/1.8.0"
+            },
+            "time": "2025-11-02T17:51:19+00:00"
+        },
+        {
+            "name": "slim/slim",
+            "version": "4.15.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/slimphp/Slim.git",
+                "reference": "887893516557506f254d950425ce7f5387a26970"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/slimphp/Slim/zipball/887893516557506f254d950425ce7f5387a26970",
+                "reference": "887893516557506f254d950425ce7f5387a26970",
+                "shasum": ""
+            },
+            "require": {
+                "ext-json": "*",
+                "nikic/fast-route": "^1.3",
+                "php": "~7.4.0 || ~8.0.0 || ~8.1.0 || ~8.2.0 || ~8.3.0 || ~8.4.0 || ~8.5.0",
+                "psr/container": "^1.0 || ^2.0",
+                "psr/http-factory": "^1.1",
+                "psr/http-message": "^1.1 || ^2.0",
+                "psr/http-server-handler": "^1.0",
+                "psr/http-server-middleware": "^1.0",
+                "psr/log": "^1.1 || ^2.0 || ^3.0"
+            },
+            "require-dev": {
+                "adriansuter/php-autoload-override": "^1.4 || ^2",
+                "ext-simplexml": "*",
+                "guzzlehttp/psr7": "^2.6",
+                "httpsoft/http-message": "^1.1",
+                "httpsoft/http-server-request": "^1.1",
+                "laminas/laminas-diactoros": "^2.17 || ^3",
+                "nyholm/psr7": "^1.8",
+                "nyholm/psr7-server": "^1.1",
+                "phpspec/prophecy": "^1.19",
+                "phpspec/prophecy-phpunit": "^2.1",
+                "phpstan/phpstan": "^1 || ^2",
+                "phpunit/phpunit": "^9.6 || ^10 || ^11 || ^12",
+                "slim/http": "^1.3",
+                "slim/psr7": "^1.6",
+                "squizlabs/php_codesniffer": "^3.10",
+                "vimeo/psalm": "^5 || ^6"
+            },
+            "suggest": {
+                "ext-simplexml": "Needed to support XML format in BodyParsingMiddleware",
+                "ext-xml": "Needed to support XML format in BodyParsingMiddleware",
+                "php-di/php-di": "PHP-DI is the recommended container library to be used with Slim",
+                "slim/psr7": "Slim PSR-7 implementation. See https://www.slimframework.com/docs/v4/start/installation.html for more information."
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Slim\\": "Slim"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Josh Lockhart",
+                    "email": "hello@joshlockhart.com",
+                    "homepage": "https://joshlockhart.com"
+                },
+                {
+                    "name": "Andrew Smith",
+                    "email": "a.smith@silentworks.co.uk",
+                    "homepage": "https://silentworks.co.uk"
+                },
+                {
+                    "name": "Rob Allen",
+                    "email": "rob@akrabat.com",
+                    "homepage": "https://akrabat.com"
+                },
+                {
+                    "name": "Pierre Berube",
+                    "email": "pierre@lgse.com",
+                    "homepage": "https://www.lgse.com"
+                },
+                {
+                    "name": "Gabriel Manricks",
+                    "email": "gmanricks@me.com",
+                    "homepage": "http://gabrielmanricks.com"
+                }
+            ],
+            "description": "Slim is a PHP micro framework that helps you quickly write simple yet powerful web applications and APIs",
+            "homepage": "https://www.slimframework.com",
+            "keywords": [
+                "api",
+                "framework",
+                "micro",
+                "router"
+            ],
+            "support": {
+                "docs": "https://www.slimframework.com/docs/v4/",
+                "forum": "https://discourse.slimframework.com/",
+                "irc": "irc://irc.freenode.net:6667/slimphp",
+                "issues": "https://github.com/slimphp/Slim/issues",
+                "rss": "https://www.slimframework.com/blog/feed.rss",
+                "slack": "https://slimphp.slack.com/",
+                "source": "https://github.com/slimphp/Slim",
+                "wiki": "https://github.com/slimphp/Slim/wiki"
+            },
+            "funding": [
+                {
+                    "url": "https://opencollective.com/slimphp",
+                    "type": "open_collective"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/slim/slim",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2025-11-21T12:23:44+00:00"
+        }
+    ],
+    "packages-dev": [],
+    "aliases": [],
+    "minimum-stability": "stable",
+    "stability-flags": {},
+    "prefer-stable": false,
+    "prefer-lowest": false,
+    "platform": {
+        "php": "^8.1"
+    },
+    "platform-dev": {},
+    "plugin-api-version": "2.9.0"
+}
diff --git a/docker-compose.yml b/docker-compose.yml
new file mode 100644
index 0000000..28e6f2b
--- /dev/null
+++ b/docker-compose.yml
@@ -0,0 +1,18 @@
+version: '3.7'
+
+volumes:
+    logs:
+        driver: local
+
+services:
+    slim:
+        image: php:7-alpine
+        working_dir: /var/www
+        command: php -S 0.0.0.0:8080 -t public
+        environment:
+            docker: "true"
+        ports:
+            - "8080:8080"
+        volumes:
+            - .:/var/www
+            - logs:/var/www/logs
diff --git a/logs/README.md b/logs/README.md
new file mode 100644
index 0000000..d4a602e
--- /dev/null
+++ b/logs/README.md
@@ -0,0 +1 @@
+Your Slim Framework application's log files will be written to this directory.
diff --git a/phpcs.xml b/phpcs.xml
new file mode 100644
index 0000000..e5c3d04
--- /dev/null
+++ b/phpcs.xml
@@ -0,0 +1,17 @@
+<?xml version="1.0"?>
+<ruleset name="Slim coding standard">
+    <description>Slim coding standard</description>
+
+    <!-- display progress -->
+    <arg value="p"/>
+    <!-- use colors in output -->
+    <arg name="colors"/>
+
+    <!-- inherit rules from: -->
+    <rule ref="PSR12"/>
+    <rule ref="Generic.Arrays.DisallowLongArraySyntax"/>
+
+    <!-- Paths to check -->
+    <file>src</file>
+    <file>tests</file>
+</ruleset>
\ No newline at end of file
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
new file mode 100644
index 0000000..2e09595
--- /dev/null
+++ b/phpstan.neon.dist
@@ -0,0 +1,4 @@
+parameters:
+  level: 4
+  paths:
+    - src
diff --git a/phpunit.xml b/phpunit.xml
new file mode 100644
index 0000000..f830400
--- /dev/null
+++ b/phpunit.xml
@@ -0,0 +1,27 @@
+<phpunit
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/7.1/phpunit.xsd"
+    backupGlobals="false"
+    backupStaticAttributes="false"
+    beStrictAboutTestsThatDoNotTestAnything="true"
+    beStrictAboutChangesToGlobalState="true"
+    beStrictAboutOutputDuringTests="true"
+    colors="true"
+    convertErrorsToExceptions="true"
+    convertNoticesToExceptions="true"
+    convertWarningsToExceptions="true"
+    processIsolation="false"
+    stopOnFailure="false"
+    bootstrap="tests/bootstrap.php"
+>
+    <testsuites>
+        <testsuite name="Test Suite">
+            <directory>./tests/</directory>
+        </testsuite>
+    </testsuites>
+    <filter>
+        <whitelist processUncoveredFilesFromWhitelist="true">
+            <directory suffix=".php">./src/</directory>
+        </whitelist>
+    </filter>
+</phpunit>
diff --git a/public/.htaccess b/public/.htaccess
new file mode 100644
index 0000000..11b28de
--- /dev/null
+++ b/public/.htaccess
@@ -0,0 +1,4 @@
+RewriteEngine On
+RewriteCond %{REQUEST_FILENAME} !-f
+RewriteCond %{REQUEST_FILENAME} !-d
+RewriteRule ^ index.php [QSA,L]
\ No newline at end of file
diff --git a/public/index.php b/public/index.php
new file mode 100644
index 0000000..2a97b97
--- /dev/null
+++ b/public/index.php
@@ -0,0 +1,50 @@
+<?php
+
+use Slim\Factory\AppFactory;
+use Psr\Http\Message\ResponseInterface as Response;
+use Psr\Http\Message\ServerRequestInterface as Request;
+
+require __DIR__ . '/../vendor/autoload.php';
+
+$app = AppFactory::create();
+$app->addErrorMiddleware(true, true, true);
+
+// CORS Middleware
+$app->add(function (Request $request, $handler) {
+    $response = $handler->handle($request);
+    return $response
+        ->withHeader('Access-Control-Allow-Origin', '*')
+        ->withHeader('Access-Control-Allow-Headers', 'Content-Type')
+        ->withHeader('Access-Control-Allow-Methods', 'GET, OPTIONS');
+});
+
+// API Documentation
+$app->get('/', function (Request $request, Response $response) {
+    $docs = [
+        'service' => 'MTEX Mock API',
+        'version' => '1.0.0',
+        'description' => 'Simple REST API providing sample JSON data',
+        'endpoints' => [
+            'GET /' => 'API documentation',
+            'GET /users' => 'List all users',
+            'GET /users/{id}' => 'Get user by ID',
+            'GET /posts' => 'List all posts',
+            'GET /posts/{id}' => 'Get post by ID',
+            'GET /products' => 'List all products',
+            'GET /products/{id}' => 'Get product by ID',
+        ],
+        'examples' => [
+            'https://mock.mtex.dev/users',
+            'https://mock.mtex.dev/users/1',
+            'https://mock.mtex.dev/posts',
+            'https://mock.mtex.dev/products',
+        ],
+    ];
+
+    $response->getBody()->write(json_encode($docs, JSON_PRETTY_PRINT));
+    return $response->withHeader('Content-Type', 'application/json');
+});
+
+require __DIR__ . '/../src/routes.php';
+
+$app->run();
\ No newline at end of file
diff --git a/src/Application/Actions/Action.php b/src/Application/Actions/Action.php
new file mode 100644
index 0000000..1021c20
--- /dev/null
+++ b/src/Application/Actions/Action.php
@@ -0,0 +1,92 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Application\Actions;
+
+use App\Domain\DomainException\DomainRecordNotFoundException;
+use Psr\Http\Message\ResponseInterface as Response;
+use Psr\Http\Message\ServerRequestInterface as Request;
+use Psr\Log\LoggerInterface;
+use Slim\Exception\HttpBadRequestException;
+use Slim\Exception\HttpNotFoundException;
+
+abstract class Action
+{
+    protected LoggerInterface $logger;
+
+    protected Request $request;
+
+    protected Response $response;
+
+    protected array $args;
+
+    public function __construct(LoggerInterface $logger)
+    {
+        $this->logger = $logger;
+    }
+
+    /**
+     * @throws HttpNotFoundException
+     * @throws HttpBadRequestException
+     */
+    public function __invoke(Request $request, Response $response, array $args): Response
+    {
+        $this->request = $request;
+        $this->response = $response;
+        $this->args = $args;
+
+        try {
+            return $this->action();
+        } catch (DomainRecordNotFoundException $e) {
+            throw new HttpNotFoundException($this->request, $e->getMessage());
+        }
+    }
+
+    /**
+     * @throws DomainRecordNotFoundException
+     * @throws HttpBadRequestException
+     */
+    abstract protected function action(): Response;
+
+    /**
+     * @return array|object
+     */
+    protected function getFormData()
+    {
+        return $this->request->getParsedBody();
+    }
+
+    /**
+     * @return mixed
+     * @throws HttpBadRequestException
+     */
+    protected function resolveArg(string $name)
+    {
+        if (!isset($this->args[$name])) {
+            throw new HttpBadRequestException($this->request, "Could not resolve argument `{$name}`.");
+        }
+
+        return $this->args[$name];
+    }
+
+    /**
+     * @param array|object|null $data
+     */
+    protected function respondWithData($data = null, int $statusCode = 200): Response
+    {
+        $payload = new ActionPayload($statusCode, $data);
+
+        return $this->respond($payload);
+    }
+
+    protected function respond(ActionPayload $payload): Response
+    {
+        $json = json_encode($payload, JSON_PRETTY_PRINT);
+        $this->response->getBody()->write($json);
+
+        return $this->response
+                    ->withHeader('Content-Type', 'application/json')
+                    ->withStatus($payload->getStatusCode());
+    }
+}
diff --git a/src/Application/Actions/ActionError.php b/src/Application/Actions/ActionError.php
new file mode 100644
index 0000000..3a81cc5
--- /dev/null
+++ b/src/Application/Actions/ActionError.php
@@ -0,0 +1,61 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Application\Actions;
+
+use JsonSerializable;
+
+class ActionError implements JsonSerializable
+{
+    public const BAD_REQUEST = 'BAD_REQUEST';
+    public const INSUFFICIENT_PRIVILEGES = 'INSUFFICIENT_PRIVILEGES';
+    public const NOT_ALLOWED = 'NOT_ALLOWED';
+    public const NOT_IMPLEMENTED = 'NOT_IMPLEMENTED';
+    public const RESOURCE_NOT_FOUND = 'RESOURCE_NOT_FOUND';
+    public const SERVER_ERROR = 'SERVER_ERROR';
+    public const UNAUTHENTICATED = 'UNAUTHENTICATED';
+    public const VALIDATION_ERROR = 'VALIDATION_ERROR';
+    public const VERIFICATION_ERROR = 'VERIFICATION_ERROR';
+
+    private string $type;
+
+    private ?string $description;
+
+    public function __construct(string $type, ?string $description = null)
+    {
+        $this->type = $type;
+        $this->description = $description;
+    }
+
+    public function getType(): string
+    {
+        return $this->type;
+    }
+
+    public function setType(string $type): self
+    {
+        $this->type = $type;
+        return $this;
+    }
+
+    public function getDescription(): ?string
+    {
+        return $this->description;
+    }
+
+    public function setDescription(?string $description = null): self
+    {
+        $this->description = $description;
+        return $this;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize(): array
+    {
+        return [
+            'type' => $this->type,
+            'description' => $this->description,
+        ];
+    }
+}
diff --git a/src/Application/Actions/ActionPayload.php b/src/Application/Actions/ActionPayload.php
new file mode 100644
index 0000000..cbf5110
--- /dev/null
+++ b/src/Application/Actions/ActionPayload.php
@@ -0,0 +1,63 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Application\Actions;
+
+use JsonSerializable;
+
+class ActionPayload implements JsonSerializable
+{
+    private int $statusCode;
+
+    /**
+     * @var array|object|null
+     */
+    private $data;
+
+    private ?ActionError $error;
+
+    public function __construct(
+        int $statusCode = 200,
+        $data = null,
+        ?ActionError $error = null
+    ) {
+        $this->statusCode = $statusCode;
+        $this->data = $data;
+        $this->error = $error;
+    }
+
+    public function getStatusCode(): int
+    {
+        return $this->statusCode;
+    }
+
+    /**
+     * @return array|null|object
+     */
+    public function getData()
+    {
+        return $this->data;
+    }
+
+    public function getError(): ?ActionError
+    {
+        return $this->error;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize(): array
+    {
+        $payload = [
+            'statusCode' => $this->statusCode,
+        ];
+
+        if ($this->data !== null) {
+            $payload['data'] = $this->data;
+        } elseif ($this->error !== null) {
+            $payload['error'] = $this->error;
+        }
+
+        return $payload;
+    }
+}
diff --git a/src/Application/Actions/User/ListUsersAction.php b/src/Application/Actions/User/ListUsersAction.php
new file mode 100644
index 0000000..7ca74d7
--- /dev/null
+++ b/src/Application/Actions/User/ListUsersAction.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Application\Actions\User;
+
+use Psr\Http\Message\ResponseInterface as Response;
+
+class ListUsersAction extends UserAction
+{
+    /**
+     * {@inheritdoc}
+     */
+    protected function action(): Response
+    {
+        $users = $this->userRepository->findAll();
+
+        $this->logger->info("Users list was viewed.");
+
+        return $this->respondWithData($users);
+    }
+}
diff --git a/src/Application/Actions/User/UserAction.php b/src/Application/Actions/User/UserAction.php
new file mode 100644
index 0000000..4ea2d8c
--- /dev/null
+++ b/src/Application/Actions/User/UserAction.php
@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Application\Actions\User;
+
+use App\Application\Actions\Action;
+use App\Domain\User\UserRepository;
+use Psr\Log\LoggerInterface;
+
+abstract class UserAction extends Action
+{
+    protected UserRepository $userRepository;
+
+    public function __construct(LoggerInterface $logger, UserRepository $userRepository)
+    {
+        parent::__construct($logger);
+        $this->userRepository = $userRepository;
+    }
+}
diff --git a/src/Application/Actions/User/ViewUserAction.php b/src/Application/Actions/User/ViewUserAction.php
new file mode 100644
index 0000000..711cf0a
--- /dev/null
+++ b/src/Application/Actions/User/ViewUserAction.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Application\Actions\User;
+
+use Psr\Http\Message\ResponseInterface as Response;
+
+class ViewUserAction extends UserAction
+{
+    /**
+     * {@inheritdoc}
+     */
+    protected function action(): Response
+    {
+        $userId = (int) $this->resolveArg('id');
+        $user = $this->userRepository->findUserOfId($userId);
+
+        $this->logger->info("User of id `${userId}` was viewed.");
+
+        return $this->respondWithData($user);
+    }
+}
diff --git a/src/Application/Handlers/HttpErrorHandler.php b/src/Application/Handlers/HttpErrorHandler.php
new file mode 100644
index 0000000..64e02b1
--- /dev/null
+++ b/src/Application/Handlers/HttpErrorHandler.php
@@ -0,0 +1,69 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Application\Handlers;
+
+use App\Application\Actions\ActionError;
+use App\Application\Actions\ActionPayload;
+use Psr\Http\Message\ResponseInterface as Response;
+use Slim\Exception\HttpBadRequestException;
+use Slim\Exception\HttpException;
+use Slim\Exception\HttpForbiddenException;
+use Slim\Exception\HttpMethodNotAllowedException;
+use Slim\Exception\HttpNotFoundException;
+use Slim\Exception\HttpNotImplementedException;
+use Slim\Exception\HttpUnauthorizedException;
+use Slim\Handlers\ErrorHandler as SlimErrorHandler;
+use Throwable;
+
+class HttpErrorHandler extends SlimErrorHandler
+{
+    /**
+     * @inheritdoc
+     */
+    protected function respond(): Response
+    {
+        $exception = $this->exception;
+        $statusCode = 500;
+        $error = new ActionError(
+            ActionError::SERVER_ERROR,
+            'An internal error has occurred while processing your request.'
+        );
+
+        if ($exception instanceof HttpException) {
+            $statusCode = $exception->getCode();
+            $error->setDescription($exception->getMessage());
+
+            if ($exception instanceof HttpNotFoundException) {
+                $error->setType(ActionError::RESOURCE_NOT_FOUND);
+            } elseif ($exception instanceof HttpMethodNotAllowedException) {
+                $error->setType(ActionError::NOT_ALLOWED);
+            } elseif ($exception instanceof HttpUnauthorizedException) {
+                $error->setType(ActionError::UNAUTHENTICATED);
+            } elseif ($exception instanceof HttpForbiddenException) {
+                $error->setType(ActionError::INSUFFICIENT_PRIVILEGES);
+            } elseif ($exception instanceof HttpBadRequestException) {
+                $error->setType(ActionError::BAD_REQUEST);
+            } elseif ($exception instanceof HttpNotImplementedException) {
+                $error->setType(ActionError::NOT_IMPLEMENTED);
+            }
+        }
+
+        if (
+            !($exception instanceof HttpException)
+            && $exception instanceof Throwable
+            && $this->displayErrorDetails
+        ) {
+            $error->setDescription($exception->getMessage());
+        }
+
+        $payload = new ActionPayload($statusCode, null, $error);
+        $encodedPayload = json_encode($payload, JSON_PRETTY_PRINT);
+
+        $response = $this->responseFactory->createResponse($statusCode);
+        $response->getBody()->write($encodedPayload);
+
+        return $response->withHeader('Content-Type', 'application/json');
+    }
+}
diff --git a/src/Application/Handlers/ShutdownHandler.php b/src/Application/Handlers/ShutdownHandler.php
new file mode 100644
index 0000000..dc54b27
--- /dev/null
+++ b/src/Application/Handlers/ShutdownHandler.php
@@ -0,0 +1,74 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Application\Handlers;
+
+use App\Application\ResponseEmitter\ResponseEmitter;
+use Psr\Http\Message\ServerRequestInterface as Request;
+use Slim\Exception\HttpInternalServerErrorException;
+
+class ShutdownHandler
+{
+    private Request $request;
+
+    private HttpErrorHandler $errorHandler;
+
+    private bool $displayErrorDetails;
+
+    public function __construct(
+        Request $request,
+        HttpErrorHandler $errorHandler,
+        bool $displayErrorDetails
+    ) {
+        $this->request = $request;
+        $this->errorHandler = $errorHandler;
+        $this->displayErrorDetails = $displayErrorDetails;
+    }
+
+    public function __invoke()
+    {
+        $error = error_get_last();
+        if ($error) {
+            $errorFile = $error['file'];
+            $errorLine = $error['line'];
+            $errorMessage = $error['message'];
+            $errorType = $error['type'];
+            $message = 'An error while processing your request. Please try again later.';
+
+            if ($this->displayErrorDetails) {
+                switch ($errorType) {
+                    case E_USER_ERROR:
+                        $message = "FATAL ERROR: {$errorMessage}. ";
+                        $message .= " on line {$errorLine} in file {$errorFile}.";
+                        break;
+
+                    case E_USER_WARNING:
+                        $message = "WARNING: {$errorMessage}";
+                        break;
+
+                    case E_USER_NOTICE:
+                        $message = "NOTICE: {$errorMessage}";
+                        break;
+
+                    default:
+                        $message = "ERROR: {$errorMessage}";
+                        $message .= " on line {$errorLine} in file {$errorFile}.";
+                        break;
+                }
+            }
+
+            $exception = new HttpInternalServerErrorException($this->request, $message);
+            $response = $this->errorHandler->__invoke(
+                $this->request,
+                $exception,
+                $this->displayErrorDetails,
+                false,
+                false,
+            );
+
+            $responseEmitter = new ResponseEmitter();
+            $responseEmitter->emit($response);
+        }
+    }
+}
diff --git a/src/Application/Middleware/SessionMiddleware.php b/src/Application/Middleware/SessionMiddleware.php
new file mode 100644
index 0000000..d7dc923
--- /dev/null
+++ b/src/Application/Middleware/SessionMiddleware.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Application\Middleware;
+
+use Psr\Http\Message\ResponseInterface as Response;
+use Psr\Http\Message\ServerRequestInterface as Request;
+use Psr\Http\Server\MiddlewareInterface as Middleware;
+use Psr\Http\Server\RequestHandlerInterface as RequestHandler;
+
+class SessionMiddleware implements Middleware
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function process(Request $request, RequestHandler $handler): Response
+    {
+        if (isset($_SERVER['HTTP_AUTHORIZATION'])) {
+            session_start();
+            $request = $request->withAttribute('session', $_SESSION);
+        }
+
+        return $handler->handle($request);
+    }
+}
diff --git a/src/Application/ResponseEmitter/ResponseEmitter.php b/src/Application/ResponseEmitter/ResponseEmitter.php
new file mode 100644
index 0000000..8a27ae1
--- /dev/null
+++ b/src/Application/ResponseEmitter/ResponseEmitter.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Application\ResponseEmitter;
+
+use Psr\Http\Message\ResponseInterface;
+use Slim\ResponseEmitter as SlimResponseEmitter;
+
+class ResponseEmitter extends SlimResponseEmitter
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function emit(ResponseInterface $response): void
+    {
+        // This variable should be set to the allowed host from which your API can be accessed with
+        $origin = $_SERVER['HTTP_ORIGIN'] ?? '';
+
+        $response = $response
+            ->withHeader('Access-Control-Allow-Credentials', 'true')
+            ->withHeader('Access-Control-Allow-Origin', $origin)
+            ->withHeader(
+                'Access-Control-Allow-Headers',
+                'X-Requested-With, Content-Type, Accept, Origin, Authorization',
+            )
+            ->withHeader('Access-Control-Allow-Methods', 'GET, POST, PUT, PATCH, DELETE, OPTIONS')
+            ->withHeader('Cache-Control', 'no-store, no-cache, must-revalidate, max-age=0')
+            ->withAddedHeader('Cache-Control', 'post-check=0, pre-check=0')
+            ->withHeader('Pragma', 'no-cache');
+
+        if (ob_get_contents()) {
+            ob_clean();
+        }
+
+        parent::emit($response);
+    }
+}
diff --git a/src/Application/Settings/Settings.php b/src/Application/Settings/Settings.php
new file mode 100644
index 0000000..6da55e4
--- /dev/null
+++ b/src/Application/Settings/Settings.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Application\Settings;
+
+class Settings implements SettingsInterface
+{
+    private array $settings;
+
+    public function __construct(array $settings)
+    {
+        $this->settings = $settings;
+    }
+
+    /**
+     * @return mixed
+     */
+    public function get(string $key = '')
+    {
+        return (empty($key)) ? $this->settings : $this->settings[$key];
+    }
+}
diff --git a/src/Application/Settings/SettingsInterface.php b/src/Application/Settings/SettingsInterface.php
new file mode 100644
index 0000000..557d98b
--- /dev/null
+++ b/src/Application/Settings/SettingsInterface.php
@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Application\Settings;
+
+interface SettingsInterface
+{
+    /**
+     * @param string $key
+     * @return mixed
+     */
+    public function get(string $key = '');
+}
diff --git a/src/Domain/DomainException/DomainException.php b/src/Domain/DomainException/DomainException.php
new file mode 100644
index 0000000..51c2795
--- /dev/null
+++ b/src/Domain/DomainException/DomainException.php
@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Domain\DomainException;
+
+use Exception;
+
+abstract class DomainException extends Exception
+{
+}
diff --git a/src/Domain/DomainException/DomainRecordNotFoundException.php b/src/Domain/DomainException/DomainRecordNotFoundException.php
new file mode 100644
index 0000000..f3859a3
--- /dev/null
+++ b/src/Domain/DomainException/DomainRecordNotFoundException.php
@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Domain\DomainException;
+
+class DomainRecordNotFoundException extends DomainException
+{
+}
diff --git a/src/Domain/User/User.php b/src/Domain/User/User.php
new file mode 100644
index 0000000..217bb9e
--- /dev/null
+++ b/src/Domain/User/User.php
@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Domain\User;
+
+use JsonSerializable;
+
+class User implements JsonSerializable
+{
+    private ?int $id;
+
+    private string $username;
+
+    private string $firstName;
+
+    private string $lastName;
+
+    public function __construct(?int $id, string $username, string $firstName, string $lastName)
+    {
+        $this->id = $id;
+        $this->username = strtolower($username);
+        $this->firstName = ucfirst($firstName);
+        $this->lastName = ucfirst($lastName);
+    }
+
+    public function getId(): ?int
+    {
+        return $this->id;
+    }
+
+    public function getUsername(): string
+    {
+        return $this->username;
+    }
+
+    public function getFirstName(): string
+    {
+        return $this->firstName;
+    }
+
+    public function getLastName(): string
+    {
+        return $this->lastName;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize(): array
+    {
+        return [
+            'id' => $this->id,
+            'username' => $this->username,
+            'firstName' => $this->firstName,
+            'lastName' => $this->lastName,
+        ];
+    }
+}
diff --git a/src/Domain/User/UserNotFoundException.php b/src/Domain/User/UserNotFoundException.php
new file mode 100644
index 0000000..ae3d11e
--- /dev/null
+++ b/src/Domain/User/UserNotFoundException.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Domain\User;
+
+use App\Domain\DomainException\DomainRecordNotFoundException;
+
+class UserNotFoundException extends DomainRecordNotFoundException
+{
+    public $message = 'The user you requested does not exist.';
+}
diff --git a/src/Domain/User/UserRepository.php b/src/Domain/User/UserRepository.php
new file mode 100644
index 0000000..099b2bf
--- /dev/null
+++ b/src/Domain/User/UserRepository.php
@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Domain\User;
+
+interface UserRepository
+{
+    /**
+     * @return User[]
+     */
+    public function findAll(): array;
+
+    /**
+     * @param int $id
+     * @return User
+     * @throws UserNotFoundException
+     */
+    public function findUserOfId(int $id): User;
+}
diff --git a/src/Infrastructure/Persistence/User/InMemoryUserRepository.php b/src/Infrastructure/Persistence/User/InMemoryUserRepository.php
new file mode 100644
index 0000000..b85a74f
--- /dev/null
+++ b/src/Infrastructure/Persistence/User/InMemoryUserRepository.php
@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Infrastructure\Persistence\User;
+
+use App\Domain\User\User;
+use App\Domain\User\UserNotFoundException;
+use App\Domain\User\UserRepository;
+
+class InMemoryUserRepository implements UserRepository
+{
+    /**
+     * @var User[]
+     */
+    private array $users;
+
+    /**
+     * @param User[]|null $users
+     */
+    public function __construct(array $users = null)
+    {
+        $this->users = $users ?? [
+            1 => new User(1, 'bill.gates', 'Bill', 'Gates'),
+            2 => new User(2, 'steve.jobs', 'Steve', 'Jobs'),
+            3 => new User(3, 'mark.zuckerberg', 'Mark', 'Zuckerberg'),
+            4 => new User(4, 'evan.spiegel', 'Evan', 'Spiegel'),
+            5 => new User(5, 'jack.dorsey', 'Jack', 'Dorsey'),
+        ];
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function findAll(): array
+    {
+        return array_values($this->users);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function findUserOfId(int $id): User
+    {
+        if (!isset($this->users[$id])) {
+            throw new UserNotFoundException();
+        }
+
+        return $this->users[$id];
+    }
+}
diff --git a/src/data/posts.php b/src/data/posts.php
new file mode 100644
index 0000000..446f605
--- /dev/null
+++ b/src/data/posts.php
@@ -0,0 +1,28 @@
+<?php
+
+return [
+    [
+        'id' => 1,
+        'userId' => 1,
+        'title' => 'Getting Started with Slim PHP',
+        'body' => 'Slim is a PHP micro framework that helps you write simple web applications and APIs.',
+        'tags' => ['php', 'slim', 'tutorial'],
+        'published' => true,
+    ],
+    [
+        'id' => 2,
+        'userId' => 2,
+        'title' => 'REST API Best Practices',
+        'body' => 'Learn how to design clean and efficient REST APIs.',
+        'tags' => ['api', 'rest', 'best-practices'],
+        'published' => true,
+    ],
+    [
+        'id' => 3,
+        'userId' => 1,
+        'title' => 'Mock Data for Testing',
+        'body' => 'Why using mock data is essential for rapid development.',
+        'tags' => ['testing', 'mock', 'development'],
+        'published' => false,
+    ],
+];
\ No newline at end of file
diff --git a/src/data/products.php b/src/data/products.php
new file mode 100644
index 0000000..c7cbf79
--- /dev/null
+++ b/src/data/products.php
@@ -0,0 +1,36 @@
+<?php
+
+return [
+    [
+        'id' => 1,
+        'name' => 'Wireless Headphones',
+        'price' => 79.99,
+        'category' => 'Electronics',
+        'inStock' => true,
+        'rating' => 4.5,
+    ],
+    [
+        'id' => 2,
+        'name' => 'Coffee Maker',
+        'price' => 49.99,
+        'category' => 'Home & Kitchen',
+        'inStock' => true,
+        'rating' => 4.2,
+    ],
+    [
+        'id' => 3,
+        'name' => 'Running Shoes',
+        'price' => 89.99,
+        'category' => 'Sports',
+        'inStock' => false,
+        'rating' => 4.8,
+    ],
+    [
+        'id' => 4,
+        'name' => 'Desk Lamp',
+        'price' => 29.99,
+        'category' => 'Home & Office',
+        'inStock' => true,
+        'rating' => 4.0,
+    ],
+];
\ No newline at end of file
diff --git a/src/data/users.php b/src/data/users.php
new file mode 100644
index 0000000..322f991
--- /dev/null
+++ b/src/data/users.php
@@ -0,0 +1,32 @@
+<?php
+
+return [
+    [
+        'id' => 1,
+        'name' => 'Alice Johnson',
+        'email' => 'alice@example.mtex.dev',
+        'role' => 'admin',
+        'active' => true,
+    ],
+    [
+        'id' => 2,
+        'name' => 'Bob Smith',
+        'email' => 'bob@example.mtex.dev',
+        'role' => 'user',
+        'active' => true,
+    ],
+    [
+        'id' => 3,
+        'name' => 'Charlie Brown',
+        'email' => 'charlie@example.mtex.dev',
+        'role' => 'user',
+        'active' => false,
+    ],
+    [
+        'id' => 4,
+        'name' => 'Diana Prince',
+        'email' => 'diana@example.mtex.dev',
+        'role' => 'moderator',
+        'active' => true,
+    ],
+];
\ No newline at end of file
diff --git a/src/routes.php b/src/routes.php
new file mode 100644
index 0000000..33176d0
--- /dev/null
+++ b/src/routes.php
@@ -0,0 +1,86 @@
+<?php
+
+use Psr\Http\Message\ResponseInterface as Response;
+use Psr\Http\Message\ServerRequestInterface as Request;
+
+// Users Routes
+$app->get('/users', function (Request $request, Response $response) {
+    $users = require __DIR__ . '/data/users.php';
+    $response->getBody()->write(json_encode($users, JSON_PRETTY_PRINT));
+    return $response->withHeader('Content-Type', 'application/json');
+});
+
+$app->get('/users/{id}', function (Request $request, Response $response, $args) {
+    $users = require __DIR__ . '/data/users.php';
+    $id = (int) $args['id'];
+
+    $user = array_values(array_filter($users, fn($u) => $u['id'] === $id));
+
+    if (empty($user)) {
+        $error = ['error' => 'User not found'];
+        $response->getBody()->write(json_encode($error));
+        return $response
+            ->withHeader('Content-Type', 'application/json')
+            ->withStatus(404);
+    }
+
+    $response->getBody()->write(json_encode($user[0], JSON_PRETTY_PRINT));
+    return $response->withHeader('Content-Type', 'application/json');
+});
+
+// Posts Routes
+$app->get('/posts', function (Request $request, Response $response) {
+    $posts = require __DIR__ . '/data/posts.php';
+    $response->getBody()->write(json_encode($posts, JSON_PRETTY_PRINT));
+    return $response->withHeader('Content-Type', 'application/json');
+});
+
+$app->get('/posts/{id}', function (Request $request, Response $response, $args) {
+    $posts = require __DIR__ . '/data/posts.php';
+    $id = (int) $args['id'];
+
+    $post = array_values(array_filter($posts, fn($p) => $p['id'] === $id));
+
+    if (empty($post)) {
+        $error = ['error' => 'Post not found'];
+        $response->getBody()->write(json_encode($error));
+        return $response
+            ->withHeader('Content-Type', 'application/json')
+            ->withStatus(404);
+    }
+
+    $response->getBody()->write(json_encode($post[0], JSON_PRETTY_PRINT));
+    return $response->withHeader('Content-Type', 'application/json');
+});
+
+// Products Routes
+$app->get('/products', function (Request $request, Response $response) {
+    $products = require __DIR__ . '/data/products.php';
+    $response->getBody()->write(json_encode($products, JSON_PRETTY_PRINT));
+    return $response->withHeader('Content-Type', 'application/json');
+});
+
+$app->get(
+    '/products/{id}',
+    function (Request $request, Response $response, $args) {
+        $products = require __DIR__ . '/data/products.php';
+        $id = (int) $args['id'];
+
+        $product = array_values(
+            array_filter($products, fn($p) => $p['id'] === $id)
+        );
+
+        if (empty($product)) {
+            $error = ['error' => 'Product not found'];
+            $response->getBody()->write(json_encode($error));
+            return $response
+                ->withHeader('Content-Type', 'application/json')
+                ->withStatus(404);
+        }
+
+        $response->getBody()->write(
+            json_encode($product[0], JSON_PRETTY_PRINT)
+        );
+        return $response->withHeader('Content-Type', 'application/json');
+    }
+);
\ No newline at end of file
diff --git a/tests/Application/Actions/ActionTest.php b/tests/Application/Actions/ActionTest.php
new file mode 100644
index 0000000..9881c68
--- /dev/null
+++ b/tests/Application/Actions/ActionTest.php
@@ -0,0 +1,79 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Application\Actions;
+
+use App\Application\Actions\Action;
+use App\Application\Actions\ActionPayload;
+use DateTimeImmutable;
+use Psr\Http\Message\ResponseInterface as Response;
+use Psr\Log\LoggerInterface;
+use Tests\TestCase;
+
+class ActionTest extends TestCase
+{
+    public function testActionSetsHttpCodeInRespond()
+    {
+        $app = $this->getAppInstance();
+        $container = $app->getContainer();
+        $logger = $container->get(LoggerInterface::class);
+
+        $testAction = new class ($logger) extends Action {
+            public function __construct(
+                LoggerInterface $loggerInterface
+            ) {
+                parent::__construct($loggerInterface);
+            }
+
+            public function action(): Response
+            {
+                return $this->respond(
+                    new ActionPayload(
+                        202,
+                        [
+                            'willBeDoneAt' => (new DateTimeImmutable())->format(DateTimeImmutable::ATOM)
+                        ]
+                    )
+                );
+            }
+        };
+
+        $app->get('/test-action-response-code', $testAction);
+        $request = $this->createRequest('GET', '/test-action-response-code');
+        $response = $app->handle($request);
+
+        $this->assertEquals(202, $response->getStatusCode());
+    }
+
+    public function testActionSetsHttpCodeRespondData()
+    {
+        $app = $this->getAppInstance();
+        $container = $app->getContainer();
+        $logger = $container->get(LoggerInterface::class);
+
+        $testAction = new class ($logger) extends Action {
+            public function __construct(
+                LoggerInterface $loggerInterface
+            ) {
+                parent::__construct($loggerInterface);
+            }
+
+            public function action(): Response
+            {
+                return $this->respondWithData(
+                    [
+                        'willBeDoneAt' => (new DateTimeImmutable())->format(DateTimeImmutable::ATOM)
+                    ],
+                    202
+                );
+            }
+        };
+
+        $app->get('/test-action-response-code', $testAction);
+        $request = $this->createRequest('GET', '/test-action-response-code');
+        $response = $app->handle($request);
+
+        $this->assertEquals(202, $response->getStatusCode());
+    }
+}
diff --git a/tests/Application/Actions/User/ListUserActionTest.php b/tests/Application/Actions/User/ListUserActionTest.php
new file mode 100644
index 0000000..fcf3222
--- /dev/null
+++ b/tests/Application/Actions/User/ListUserActionTest.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Application\Actions\User;
+
+use App\Application\Actions\ActionPayload;
+use App\Domain\User\UserRepository;
+use App\Domain\User\User;
+use DI\Container;
+use Tests\TestCase;
+
+class ListUserActionTest extends TestCase
+{
+    public function testAction()
+    {
+        $app = $this->getAppInstance();
+
+        /** @var Container $container */
+        $container = $app->getContainer();
+
+        $user = new User(1, 'bill.gates', 'Bill', 'Gates');
+
+        $userRepositoryProphecy = $this->prophesize(UserRepository::class);
+        $userRepositoryProphecy
+            ->findAll()
+            ->willReturn([$user])
+            ->shouldBeCalledOnce();
+
+        $container->set(UserRepository::class, $userRepositoryProphecy->reveal());
+
+        $request = $this->createRequest('GET', '/users');
+        $response = $app->handle($request);
+
+        $payload = (string) $response->getBody();
+        $expectedPayload = new ActionPayload(200, [$user]);
+        $serializedPayload = json_encode($expectedPayload, JSON_PRETTY_PRINT);
+
+        $this->assertEquals($serializedPayload, $payload);
+    }
+}
diff --git a/tests/Application/Actions/User/ViewUserActionTest.php b/tests/Application/Actions/User/ViewUserActionTest.php
new file mode 100644
index 0000000..785b6c6
--- /dev/null
+++ b/tests/Application/Actions/User/ViewUserActionTest.php
@@ -0,0 +1,80 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Application\Actions\User;
+
+use App\Application\Actions\ActionError;
+use App\Application\Actions\ActionPayload;
+use App\Application\Handlers\HttpErrorHandler;
+use App\Domain\User\User;
+use App\Domain\User\UserNotFoundException;
+use App\Domain\User\UserRepository;
+use DI\Container;
+use Slim\Middleware\ErrorMiddleware;
+use Tests\TestCase;
+
+class ViewUserActionTest extends TestCase
+{
+    public function testAction()
+    {
+        $app = $this->getAppInstance();
+
+        /** @var Container $container */
+        $container = $app->getContainer();
+
+        $user = new User(1, 'bill.gates', 'Bill', 'Gates');
+
+        $userRepositoryProphecy = $this->prophesize(UserRepository::class);
+        $userRepositoryProphecy
+            ->findUserOfId(1)
+            ->willReturn($user)
+            ->shouldBeCalledOnce();
+
+        $container->set(UserRepository::class, $userRepositoryProphecy->reveal());
+
+        $request = $this->createRequest('GET', '/users/1');
+        $response = $app->handle($request);
+
+        $payload = (string) $response->getBody();
+        $expectedPayload = new ActionPayload(200, $user);
+        $serializedPayload = json_encode($expectedPayload, JSON_PRETTY_PRINT);
+
+        $this->assertEquals($serializedPayload, $payload);
+    }
+
+    public function testActionThrowsUserNotFoundException()
+    {
+        $app = $this->getAppInstance();
+
+        $callableResolver = $app->getCallableResolver();
+        $responseFactory = $app->getResponseFactory();
+
+        $errorHandler = new HttpErrorHandler($callableResolver, $responseFactory);
+        $errorMiddleware = new ErrorMiddleware($callableResolver, $responseFactory, true, false, false);
+        $errorMiddleware->setDefaultErrorHandler($errorHandler);
+
+        $app->add($errorMiddleware);
+
+        /** @var Container $container */
+        $container = $app->getContainer();
+
+        $userRepositoryProphecy = $this->prophesize(UserRepository::class);
+        $userRepositoryProphecy
+            ->findUserOfId(1)
+            ->willThrow(new UserNotFoundException())
+            ->shouldBeCalledOnce();
+
+        $container->set(UserRepository::class, $userRepositoryProphecy->reveal());
+
+        $request = $this->createRequest('GET', '/users/1');
+        $response = $app->handle($request);
+
+        $payload = (string) $response->getBody();
+        $expectedError = new ActionError(ActionError::RESOURCE_NOT_FOUND, 'The user you requested does not exist.');
+        $expectedPayload = new ActionPayload(404, null, $expectedError);
+        $serializedPayload = json_encode($expectedPayload, JSON_PRETTY_PRINT);
+
+        $this->assertEquals($serializedPayload, $payload);
+    }
+}
diff --git a/tests/Domain/User/UserTest.php b/tests/Domain/User/UserTest.php
new file mode 100644
index 0000000..36f4925
--- /dev/null
+++ b/tests/Domain/User/UserTest.php
@@ -0,0 +1,60 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Domain\User;
+
+use App\Domain\User\User;
+use Tests\TestCase;
+
+class UserTest extends TestCase
+{
+    public function userProvider(): array
+    {
+        return [
+            [1, 'bill.gates', 'Bill', 'Gates'],
+            [2, 'steve.jobs', 'Steve', 'Jobs'],
+            [3, 'mark.zuckerberg', 'Mark', 'Zuckerberg'],
+            [4, 'evan.spiegel', 'Evan', 'Spiegel'],
+            [5, 'jack.dorsey', 'Jack', 'Dorsey'],
+        ];
+    }
+
+    /**
+     * @dataProvider userProvider
+     * @param int    $id
+     * @param string $username
+     * @param string $firstName
+     * @param string $lastName
+     */
+    public function testGetters(int $id, string $username, string $firstName, string $lastName)
+    {
+        $user = new User($id, $username, $firstName, $lastName);
+
+        $this->assertEquals($id, $user->getId());
+        $this->assertEquals($username, $user->getUsername());
+        $this->assertEquals($firstName, $user->getFirstName());
+        $this->assertEquals($lastName, $user->getLastName());
+    }
+
+    /**
+     * @dataProvider userProvider
+     * @param int    $id
+     * @param string $username
+     * @param string $firstName
+     * @param string $lastName
+     */
+    public function testJsonSerialize(int $id, string $username, string $firstName, string $lastName)
+    {
+        $user = new User($id, $username, $firstName, $lastName);
+
+        $expectedPayload = json_encode([
+            'id' => $id,
+            'username' => $username,
+            'firstName' => $firstName,
+            'lastName' => $lastName,
+        ]);
+
+        $this->assertEquals($expectedPayload, json_encode($user));
+    }
+}
diff --git a/tests/Infrastructure/Persistence/User/InMemoryUserRepositoryTest.php b/tests/Infrastructure/Persistence/User/InMemoryUserRepositoryTest.php
new file mode 100644
index 0000000..6b51b0c
--- /dev/null
+++ b/tests/Infrastructure/Persistence/User/InMemoryUserRepositoryTest.php
@@ -0,0 +1,53 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Infrastructure\Persistence\User;
+
+use App\Domain\User\User;
+use App\Domain\User\UserNotFoundException;
+use App\Infrastructure\Persistence\User\InMemoryUserRepository;
+use Tests\TestCase;
+
+class InMemoryUserRepositoryTest extends TestCase
+{
+    public function testFindAll()
+    {
+        $user = new User(1, 'bill.gates', 'Bill', 'Gates');
+
+        $userRepository = new InMemoryUserRepository([1 => $user]);
+
+        $this->assertEquals([$user], $userRepository->findAll());
+    }
+
+    public function testFindAllUsersByDefault()
+    {
+        $users = [
+            1 => new User(1, 'bill.gates', 'Bill', 'Gates'),
+            2 => new User(2, 'steve.jobs', 'Steve', 'Jobs'),
+            3 => new User(3, 'mark.zuckerberg', 'Mark', 'Zuckerberg'),
+            4 => new User(4, 'evan.spiegel', 'Evan', 'Spiegel'),
+            5 => new User(5, 'jack.dorsey', 'Jack', 'Dorsey'),
+        ];
+
+        $userRepository = new InMemoryUserRepository();
+
+        $this->assertEquals(array_values($users), $userRepository->findAll());
+    }
+
+    public function testFindUserOfId()
+    {
+        $user = new User(1, 'bill.gates', 'Bill', 'Gates');
+
+        $userRepository = new InMemoryUserRepository([1 => $user]);
+
+        $this->assertEquals($user, $userRepository->findUserOfId(1));
+    }
+
+    public function testFindUserOfIdThrowsNotFoundException()
+    {
+        $userRepository = new InMemoryUserRepository([]);
+        $this->expectException(UserNotFoundException::class);
+        $userRepository->findUserOfId(1);
+    }
+}
diff --git a/tests/TestCase.php b/tests/TestCase.php
new file mode 100644
index 0000000..a55f09d
--- /dev/null
+++ b/tests/TestCase.php
@@ -0,0 +1,90 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests;
+
+use DI\ContainerBuilder;
+use Exception;
+use PHPUnit\Framework\TestCase as PHPUnit_TestCase;
+use Prophecy\PhpUnit\ProphecyTrait;
+use Psr\Http\Message\ServerRequestInterface as Request;
+use Slim\App;
+use Slim\Factory\AppFactory;
+use Slim\Psr7\Factory\StreamFactory;
+use Slim\Psr7\Headers;
+use Slim\Psr7\Request as SlimRequest;
+use Slim\Psr7\Uri;
+
+class TestCase extends PHPUnit_TestCase
+{
+    use ProphecyTrait;
+
+    /**
+     * @return App
+     * @throws Exception
+     */
+    protected function getAppInstance(): App
+    {
+        // Instantiate PHP-DI ContainerBuilder
+        $containerBuilder = new ContainerBuilder();
+
+        // Container intentionally not compiled for tests.
+
+        // Set up settings
+        $settings = require __DIR__ . '/../app/settings.php';
+        $settings($containerBuilder);
+
+        // Set up dependencies
+        $dependencies = require __DIR__ . '/../app/dependencies.php';
+        $dependencies($containerBuilder);
+
+        // Set up repositories
+        $repositories = require __DIR__ . '/../app/repositories.php';
+        $repositories($containerBuilder);
+
+        // Build PHP-DI Container instance
+        $container = $containerBuilder->build();
+
+        // Instantiate the app
+        AppFactory::setContainer($container);
+        $app = AppFactory::create();
+
+        // Register middleware
+        $middleware = require __DIR__ . '/../app/middleware.php';
+        $middleware($app);
+
+        // Register routes
+        $routes = require __DIR__ . '/../app/routes.php';
+        $routes($app);
+
+        return $app;
+    }
+
+    /**
+     * @param string $method
+     * @param string $path
+     * @param array  $headers
+     * @param array  $cookies
+     * @param array  $serverParams
+     * @return Request
+     */
+    protected function createRequest(
+        string $method,
+        string $path,
+        array $headers = ['HTTP_ACCEPT' => 'application/json'],
+        array $cookies = [],
+        array $serverParams = []
+    ): Request {
+        $uri = new Uri('', '', 80, $path);
+        $handle = fopen('php://temp', 'w+');
+        $stream = (new StreamFactory())->createStreamFromResource($handle);
+
+        $h = new Headers();
+        foreach ($headers as $name => $value) {
+            $h->addHeader($name, $value);
+        }
+
+        return new SlimRequest($method, $uri, $h, $cookies, $serverParams, $stream);
+    }
+}
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
new file mode 100644
index 0000000..d21c14d
--- /dev/null
+++ b/tests/bootstrap.php
@@ -0,0 +1,3 @@
+<?php
+
+require __DIR__ . '/../vendor/autoload.php';
diff --git a/var/cache/.gitignore b/var/cache/.gitignore
new file mode 100644
index 0000000..d6b7ef3
--- /dev/null
+++ b/var/cache/.gitignore
@@ -0,0 +1,2 @@
+*
+!.gitignore