cPanel is a Unix based web hosting control panel that provides a graphical interface and automation tools designed to simplify the process of hosting a web site. cPanel utilizes a 3-tier structure that provides functionality for administrators, resellers, and end-user website owners to control the various aspects of website and server administration through a standard web browser. 

In addition to the GUI interface cPanel also has command line and API based access that allows third party software vendors, web hosting organizations, and developers to automate standard system administration processes. 

cPanel is designed to function either as a dedicated server or virtual private server and it supports CentOS, Red Hat Linux, and FreeBSD. Application-based support includes Apache, PHP, MySQL, Postgres, Perl, and BIND (DNS). Email based support includes POP3, IMAP, SMTP services. cPanel is commonly accessed on port 2082, with an SSL-secured server operating on port 2083. 

To the client, cPanel provides front-ends for a number of common operations, including the management of PGP keys, crontab tasks, mail and FTP accounts, and mailing lists. 

Several add-ons exist for an additional fee, the most notable being Auto Installers like Fantastico, Softaculous, WHMSonic(Shoutcast/radio Control Panel Add-on) and Installatron. Auto Installers are a bundle of scripts which automate the installation and update of, web applications such as WordPress, SMF, phpBB, Drupal, Joomla!, Tiki Wiki CMS Groupware, Moodle, WHMCS, ZamFoo and over 100 others. Fantastico is a popular Auto Installer but is losing market fast because of lack of updates (see article) and fewer number of scripts. 

cPanel manages some software packages separately from the underlying operating system, applying upgrades to Apache, PHP, MySQL, and related software packages automatically. This ensures that these packages are kept up-to-date and compatible with cPanel, but makes it more difficult to install newer versions of these packages. 

One very unique feature of cPanel is Web Host Manager. WebHost Manager (WHM) is a web-based tool used by server administrators and resellers to manage hosting accounts on a web server. As well as being accessible by the root admin, WHM is also accessible to users with reseller privileges. Reseller users of cPanel have a smaller set of features than the root user, generally limited by the server administrator, to features which they determine will affect their customers' accounts rather than the server as a whole. From WHM, the server administrator can perform maintenance operations such as compile Apache and upgrade RPMs installed on the system.