WHMCS supports several authentication methods for logging in to WHMCS and for authenticating in custom development.


Your WHMCS system's automation settings determine how it performs tasks like generating invoices or sending emails.

Database and Storage

WHMCS stores all of your business's data in a MySQL® database. Make sure you back it up regularly.


Email tools make it easy to create email campaigns, customize messages, and stay in touch with clients.

General Settings

Your General Settings configuration controls many of the most important settings in WHMCS.


The customizable localization system lets your admins and users view WHMCS in their chosen languages.


WHMCS runs on PHP. Make sure your server's PHP configuration meets our requirements.


The update system helps you stay up-to-date with WHMCS's releases, ensuring continued support on the latest version.

System Tutorials

How-to guides for performing general system tasks like changing the system theme or forcing license updates.

Trusted Proxies

Use the Trusted Proxies setting to itemize IP addresses or ranges for detecting inbound traffic.