A plug-in is a small software component (module) created as a supplement to the main program. As a rule, it is a small program that improves and extends the capabilities of the main program.

How it works

Since a plugin is a component of an application, it is not used separately and is dependent on the main program. An installed plug-in is registered in the application and can exchange data with other modules. If an application receives a request that it cannot handle by itself, a plugin receives the corresponding command and handles the request.

Using plug-ins

These modules are used in many programs, from a music player or a graphic editor to an Internet browser or a website management system (CMS). For example, without installed plugin Adobe Flash Player, most browsers can not display multimedia content on the site, and without a component Java Toolkit sites that use Java applications will not work correctly. Important components of browsers are also modules that allow you to work with text files: Adobe Acrobat plugin for viewing *pdf documents, Microsoft Office system module – for working with documents of Microsoft Office, etc.

Plug-ins and CMS

The functionality of almost any CMS allows you to connect to the already installed scripts, additional plug-ins. To do this, in the code of the module is designated where and when it should connect to the engine. Installation can be either manual, when the module must be copied into the directory and added to the site, or automatic.

Working principle

The installed plugin is added to the list of CMS programs and runs when needed. Usually plugins are placed in a separate directory from the main directory – this greatly simplifies the mechanism for updating the program itself and the CMS as a whole: in the event of a failure during system updates, plugins that are stored in a separate folder will not be damaged.

Plugins features

Most CMS support installation of third-party add-ons.

With the help of plug-ins can:

  • improve the functionality of the administrative part of the site;
  • increase its speed (some plugins optimize the use of cache memory);
  • increase site security;
  • obtain additional opportunities to manage media content;
  • improve the appearance of the site;
  • customize mailing lists;
  • facilitate promotion of the site in search engines (using SEO-plugins and modules for working with social networks);
  • significantly improve usability.

Advantages and disadvantages of using plugins


  • expanding the capabilities of the main program;
  • ease of installation and use: many plugins do not require knowledge of programming languages for installation and configuration;
  • Availability: a large number of modules are developed under the GNU Generic Public License, which means that there is no charge for their use.

The disadvantages include:

  • conflict of modules in the case of use within the same CMS plugins from different authors (the creation of modules engaged in a huge number of developers around the world);
  • Additional load on the server, which may be either negligible or sufficiently high – depending on the purpose of the module, its functionality and compatibility with the system.