How to Install WHMCS on Debian 13

WHMCS is the most widely used billing and automation platform for hosting companies, VPS providers, and domain resellers. Debian 13 (Trixie) provides a stable, high-performance base for running WHMCS with Apache, PHP, and MariaDB.

Step 1: Update System Packages

Start by updating your Debian 13 server:

sudo apt update && sudo apt upgrade -y

Step 2: Install Apache Web Server

WHMCS works best with Apache.

sudo apt install apache2 -y
sudo systemctl enable --now apache2

Check service status:

systemctl status apache2

Step 3: Install PHP and Required Extensions

WHMCS requires specific PHP modules. Install them all at once:

sudo apt install -y php php-cli php-fpm php-mysql php-curl php-zip php-xml php-json php-mbstring php-gd php-intl php-opcache php-bcmath php-imagick

Restart Apache:

sudo systemctl restart apache2

Verify PHP version:

php -v

Step 4: Install MariaDB Server

WHMCS uses MySQL/MariaDB for data storage:

sudo apt install mariadb-server -y
sudo systemctl enable --now mariadb
sudo mysql_secure_installation

Step 5: Create WHMCS Database and User

sudo mysql -u root

Then run:

CREATE DATABASE whmcs;
CREATE USER 'whmcsuser'@'localhost' IDENTIFIED BY 'StrongPasswordHere';
GRANT ALL PRIVILEGES ON whmcs.* TO 'whmcsuser'@'localhost';
FLUSH PRIVILEGES;
EXIT;

Step 6: Download and Upload WHMCS

WHMCS requires a valid license, so download it from your WHMCS client area.
Upload the ZIP to your server via SFTP or your hosting panel.

Move to your web root:

cd /var/www/

Extract:

sudo unzip whmcs.zip -d whmcs

Set proper permissions:

sudo chown -R www-data:www-data whmcs
sudo chmod -R 755 whmcs

Step 7: Configure Apache Virtual Host

Create a configuration file:

sudo nano /etc/apache2/sites-available/whmcs.conf

Add:

<VirtualHost *:80>
    ServerName your-domain.com
    DocumentRoot /var/www/whmcs

    <Directory /var/www/whmcs/>
        AllowOverride All
        Require all granted
    </Directory>

    ErrorLog ${APACHE_LOG_DIR}/whmcs-error.log
    CustomLog ${APACHE_LOG_DIR}/whmcs-access.log combined
</VirtualHost>

Enable site + modules:

sudo a2ensite whmcs.conf
sudo a2enmod rewrite
sudo systemctl restart apache2

Step 8: Install IonCube Loader (Required)

WHMCS will not run without IonCube.

Download:

cd /tmp
wget https://downloads.ioncube.com/loader_downloads/ioncube_loaders_lin_x86-64.tar.gz
tar xvf ioncube_loaders_lin_x86-64.tar.gz

Find PHP’s extension directory:

php -i | grep extension_dir

Copy the correct loader:

sudo cp ioncube/ioncube_loader_lin_8.2.so /usr/lib/php/20230831/

Enable it:

echo "zend_extension=/usr/lib/php/20230831/ioncube_loader_lin_8.2.so" | sudo tee /etc/php/8.2/apache2/conf.d/00-ioncube.ini

Restart Apache:

sudo systemctl restart apache2

Step 9: Run WHMCS Installer

Visit:

http://your-domain.com/install

Complete the wizard:

Enter database credentials
Enter your WHMCS license key
Create admin account

After the installation finishes, remove the installer:

sudo rm -rf /var/www/whmcs/install

Optional Step: Enable HTTPS with Certbot

To secure WHMCS with SSL:

sudo apt install certbot python3-certbot-apache -y
sudo certbot --apache

This automatically configures HTTPS. WHMCS stores customer data, invoices, payment logs, and API credentials — set up automated backups for both your WHMCS directory and its database to avoid data loss.