The five extension types
Joomla distinguishes five kinds of extensions that together form the CMS’s modular system:
- Components – standalone applications with primary functionality, e.g. shops, forms, galleries.
- Modules – small content blocks for sidebars, headers, or footers that display additional information.
- Plugins – background functions that extend the system, e.g. for login authentication or content enhancement.
- Templates – design templates that determine the site’s layout and appearance.
- Languages – translation packages that make Joomla and extensions multilingual.
Common use cases
Extensions are used whenever the Joomla core installation isn’t enough. Typical scenarios include:
- E‑Commerce – for example with HikaShop or VirtueMart
- Forms and surveys – e.g. RSForm! or BreezingForms
- Multilingual sites – using extensions like Falang
- Membership management – e.g. Community Builder or JomSocial
- SEO and performance – e.g. sh404SEF or Regular Labs Cache Cleaner
Practical notes
Extensions offer huge flexibility — but they also carry risks if not maintained. In practice:
- Check for updates: Outdated extensions are the most common cause of hacked Joomla sites. Keep plugins, components, and modules up to date; use the Joomla Update feature.
- Use reputable sources only: Install extensions only from the Joomla Extensions Directory (JED) or trusted developers.
- Watch performance: Too many extensions (more than 15–20) can significantly increase load times and complicate maintenance.
- Use staging: Always test new extensions in a staging environment before deploying them live.