diff --git a/.circleci/config.yml b/.circleci/config.yml
new file mode 100644
index 0000000..0fc42c6
--- /dev/null
+++ b/.circleci/config.yml
@@ -0,0 +1,107 @@
+version: 2
+
+jobs:
+  backend:
+    docker:
+      - image: circleci/php:7.2-stretch
+        environment:
+          ag44jc7aqs2rsup2bb6cx7utc: '127.0.0.1' # 'mysql-url'
+          hp7wz20wu4qfbfcmqywfai1j4: tempfiles # 'mysql-user'
+          mom8c5hrbn8c1r5lro1imfyax: thisisonlyusedfortestinganyways # 'mysql-password'
+          qb1yi60nrz3tjjjqqb7l2yqra: tempfiles # 'mysql-db'
+          rb421p9wniz81ttj7bdgrg0ub: tempfiles # 'mysql-table'
+      - image: circleci/mariadb:10-bionic-ram
+        environment:
+          MYSQL_DATABASE: tempfiles
+          MYSQL_USER: tempfiles
+          MYSQL_PASSWORD: thisisonlyusedfortestinganyways
+    steps:
+      - checkout
+
+      - restore_cache:
+          key: composer-cache-{{ checksum "backend/composer.lock" }}
+
+      - run:
+          name: Composer install
+          command: "cd backend && composer install"
+
+      - save_cache:
+          paths:
+            - backend/vendor
+          key: composer-cache-{{ checksum "backend/composer.lock" }}
+
+      - run:
+          name: Install PHP extensions
+          command: sudo docker-php-ext-install -j$(nproc) mysqli
+
+      - run:
+          name: Install MySQL Client
+          command: |
+            sudo apt update
+            sudo apt install -y mysql-client
+
+      - run:
+          name: Waiting for Mariadb to be ready
+          command: |
+            for i in `seq 1 10`;
+            do
+              nc -z localhost 3306 && echo Success && exit 0
+              echo -n .
+              sleep 1
+            done
+            echo Failed waiting for Mariadb && exit 1
+
+      - run:
+          name: Create database & table
+          command: mysql --protocol=tcp --host=localhost --port=3306 --user=$hp7wz20wu4qfbfcmqywfai1j4 --password=$mom8c5hrbn8c1r5lro1imfyax < resources/install_mysql.sql
+
+      - run:
+          name: "Run PHP Unit Tests"
+          command: "./backend/vendor/phpunit/phpunit/phpunit --configuration ./circleci/phpunit.xml --teamcity"
+
+  frontend:
+    docker:
+      - image: circleci/ruby:2
+    steps:
+      - checkout
+
+      - restore_cache:
+          keys:
+            - gem-cache-{{ checksum "frontend/Gemfile.lock" }}
+
+      - run:
+          name: Bundle install
+          command: cd frontend && bundle install --path vendor/bundle
+
+      - save_cache:
+          paths:
+            - frontend/vendor/bundle
+          key: gem-cache-{{ checksum "frontend/Gemfile.lock" }}
+
+      - run:
+          name: Build frontend
+          command: cd frontend && bundle exec rake proof build
+
+  # deploy:
+  #   machine:
+  #     enabled: true
+  #   steps:
+  #     - run:
+  #         name: Trigger Webhook
+  #         command: # curl?
+
+
+
+workflows:
+  version: 2
+  test:
+    jobs:
+      - backend
+      - frontend
+      # - deploy:
+      #     requires:
+      #       - backend
+      #       - frontend
+      #     filters:
+      #       branches:
+      #         only: master
diff --git a/.circleci/phpunit.xml b/.circleci/phpunit.xml
new file mode 100644
index 0000000..276b776
--- /dev/null
+++ b/.circleci/phpunit.xml
@@ -0,0 +1,12 @@
+<phpunit bootstrap="./backend/src/com/carlgo11/tempfiles/Autoload.php" colors="true">
+    <testsuites>
+        <testsuite name="tempfiles">
+            <directory>./backend/tests</directory>
+        </testsuite>
+    </testsuites>
+    <filter>
+        <whitelist>
+            <directory>./backend/src</directory>
+        </whitelist>
+    </filter>
+</phpunit>
\ No newline at end of file
diff --git a/.travis.yml b/.travis.yml
index 8381541..236b66d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,8 +4,8 @@ matrix:
   include:
     - language: php
       php:
-        - 7.2
-        - 7.3
+        - "7.2"
+        - "7.3"
       before_install:
         - cd backend
       install:
@@ -20,7 +20,8 @@ matrix:
         - 2.4.1
       cache:
         bundler: true
-        directories: $TRAVIS_BUILD_DIR/tmp/.htmlproofer
+        directories:
+          - $TRAVIS_BUILD_DIR/tmp/.htmlproofer
       before_install:
         - cd frontend
       script:
diff --git a/backend/composer.json b/backend/composer.json
index 70372cf..7ae5d22 100644
--- a/backend/composer.json
+++ b/backend/composer.json
@@ -2,5 +2,8 @@
   "require-dev": {
     "phpunit/phpunit": "^8.1",
     "phpunit/php-code-coverage": "^7.0"
+  },
+  "require": {
+    "ext-mysqli": "*"
   }
 }
diff --git a/backend/phpunit.xml b/backend/phpunit.xml
index a98efdc..508dd84 100644
--- a/backend/phpunit.xml
+++ b/backend/phpunit.xml
@@ -1,11 +1,12 @@
 <phpunit bootstrap="src/com/carlgo11/tempfiles/Autoload.php" colors="true">
     <testsuites>
-        <testsuite name="tempfiles">
+        <testsuite name="tempfiles-no-mysql">
             <directory>tests</directory>
+            <exclude>tests/com/carlgo11/tempfiles/DataStorageTest.php</exclude>
         </testsuite>
     </testsuites>
     <php>
-        <env name="phpunit" value="true"/>
+        <env name="ignore-mysql" value="true"/>
     </php>
     <filter>
         <whitelist>
diff --git a/backend/src/com/carlgo11/tempfiles/Autoload.php b/backend/src/com/carlgo11/tempfiles/Autoload.php
index 0ce6bb0..e205290 100644
--- a/backend/src/com/carlgo11/tempfiles/Autoload.php
+++ b/backend/src/com/carlgo11/tempfiles/Autoload.php
@@ -1,7 +1,6 @@
 <?php
 
 // Load resources.
-
 $conf = checkFile(__DIR__ . '/config.php');
 checkFile(__DIR__ . '/DataStorage.php');
 checkFile(__DIR__ . '/Encryption.php');
@@ -9,11 +8,9 @@
 checkFile(__DIR__ . '/File.php');
 checkFile(__DIR__ . '/API.php');
 
-// Load MySQL connection unless the script is run by PHPUnit.
-if (!isset($_ENV['phpunit']))
-    $mysql_connection = mysqli_connect($conf['mysql-url'], $conf['mysql-user'], $conf['mysql-password'], $conf['mysql-db'])
-    or mySQLError($mysql_connection);
-
+// Connect to the database unless run by test.
+if(!isset($_ENV['ignore-mysql']))
+    $mysql_connection = mysqli_connect($conf['mysql-url'], $conf['mysql-user'], $conf['mysql-password'], $conf['mysql-db']) or mySQLError($mysql_connection);
 
 /**
  * Outputs MySQL error.
@@ -23,7 +20,8 @@
 function mySQLError($mysql_connection) {
     error_log('MySQL connection failed: ' . htmlspecialchars($mysql_connection->error));
     http_response_code(500);
-    die("Connection to our database failed.");
+    die('Connection to our database failed.');
+    throw new Exeption('Connection to our database failed.');
 }
 
 /**
diff --git a/backend/src/com/carlgo11/tempfiles/DataStorage.php b/backend/src/com/carlgo11/tempfiles/DataStorage.php
index 0072b1d..1dc7fc2 100644
--- a/backend/src/com/carlgo11/tempfiles/DataStorage.php
+++ b/backend/src/com/carlgo11/tempfiles/DataStorage.php
@@ -174,4 +174,27 @@ public static function uploadFile(File $file, string $password) {
         }
     }
 
+    // TODO: Remove. Just an example.
+    public static function getMariaDBVersion() {
+        global $mysql_connection;
+
+        try {
+
+            $query = $mysql_connection->prepare('SELECT VERSION()');
+
+            $query->execute();
+            $query->store_result();
+            $query->bind_result($version);
+            $query->fetch();
+            $query->close();
+
+            return $version;
+
+        } catch (Exception $e) {
+            error_log($e);
+            return FALSE;
+        }
+
+    }
+
 }
diff --git a/backend/src/com/carlgo11/tempfiles/config.php b/backend/src/com/carlgo11/tempfiles/config.php
index 4dafc07..f153803 100644
--- a/backend/src/com/carlgo11/tempfiles/config.php
+++ b/backend/src/com/carlgo11/tempfiles/config.php
@@ -5,20 +5,19 @@
  * If you'd prefer to just store the credentials in this document then,
  * replace my variables definitions with the ones I've commented.
  */
-
-return array(
+return [
     # Allowed formats <n>MB, <n>GB, <n>TB, <n>PB.
     'max-file-size' => '12MB',
-    #'mysql-url' => 'localhost',
+    # 'mysql-url' => 'localhost',
     'mysql-url' => getenv('ag44jc7aqs2rsup2bb6cx7utc'),
-    #'mysql-user => 'tempfiles',
+    # 'mysql-user' => 'tempfiles',
     'mysql-user' => getenv('hp7wz20wu4qfbfcmqywfai1j4'),
-    #'mysql-password' => 'password',
+    # 'mysql-password' => 'password',
     'mysql-password' => getenv('mom8c5hrbn8c1r5lro1imfyax'),
-    #'mysql-db' => 'tempfiles',
+    # 'mysql-db' => 'tempfiles',
     'mysql-db' => getenv('qb1yi60nrz3tjjjqqb7l2yqra'),
-    #'mysql-table' => 'files',
+    # 'mysql-table' => 'files',
     'mysql-table' => getenv('rb421p9wniz81ttj7bdgrg0ub'),
     # Encryption algorithm to use for encrypting uploads.
     'Encryption-Method' => 'aes-256-gcm'
-);
+];
diff --git a/backend/tests/com/carlgo11/tempfiles/DataStorageTest.php b/backend/tests/com/carlgo11/tempfiles/DataStorageTest.php
new file mode 100644
index 0000000..6724811
--- /dev/null
+++ b/backend/tests/com/carlgo11/tempfiles/DataStorageTest.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace com\carlgo11\tempfiles;
+
+use com\carlgo11\tempfiles;
+use PHPUnit\Framework\TestCase;
+
+class DataStorageTest extends TestCase
+{
+
+    // TODO: Remove. Just an example.
+    public function testGetMariaDBVersion() {
+        $this->assertIsString(DataStorage::getMariaDBVersion());
+    }
+
+}