What is an add-on?

An add-on is an additional module or additional program. It supplements software and hardware applications by adding functions that the main program does not have. The add-on therefore changes various properties of the system in which it is implemented in order to increase the range of functions. However, an add-on cannot run without the main program, as it is not independent in its range of functions.

Add-ons are sometimes available for browsers, mail programs or games. They are offered for download and can often be installed free of charge and with just a few clicks as part of the software they are intended to supplement. The possible uses are very diverse: for example, add-ons can be used to increase security, simplify web searches or manage bookmarks.

Especially in the area of online marketing, search engine optimization or web analytics, there are a large number of add-ons and browser extensions that can make certain workflows easier:

• SEO META in 1 CLICK
  This add-on allows you to view information such as meta data, heading structure or tools used for the page you are on at a glance.
• Ghostery - privacy-oriented ad blocker
  The Ghostery add-on makes it possible to block ads, stop trackers and speed up websites.
• BuiltWith Technology Profiler
  This add-on shows the most important information regarding technological aspects, such as which CMS the website uses and which analysis and tracking tools are in use.

Another well-known add-on is the Adobe Acrobat Reader, which can be used to open PDF documents directly in the browser.

The terms add-on and plug-in are often used interchangeably. In practice, however, there is a difference, as plug-ins can also run without the main program. Detailed information on the term plug-in can be found here.