# Installed

Determine whether or not a Composer package is installed.

A common use case for this tag is if you are building a reusable site (like a Starter Kit) and you'd like
to do something differently depending on whether a package is installed.

Use this as a single tag within an `if` statement:

::tabs

::tab antlers
```antlers
{{ if {installed:statamic/seo-pro} }}
    {{ seo_pro:meta }}
{{ else }}
    {{ partial:seo }}
{{ /if }}
```
::tab blade
```blade
@if (Statamic::tag('installed:statamic/seo-pro')->fetch())
  <s:seo_pro:meta />
@else
  <s:partial:seo />
@endif
```
::

Or as a tag pair. If the package doesn't exist, then nothing between the tag will be output:

::tabs

::tab antlers
```antlers
{{ installed:statamic/seo-pro }}
    {{ seo_pro:meta }}
{{ /installed:statamic/seo-pro }}
```
::tab blade
```blade
<s:installed:statamic/seo-pro>
  <s:seo_pro:meta />
</s:installed:statamic/seo-pro>
```
::

:::tip
You can pass any Composer package name into this tag. It's not limited to Statamic addons.
:::