Twig Filters & Functions

FOSSBilling uses Twig across themes, email templates, and PDFs. This page lists the filters and functions you can rely on while building against it.

Standard Twig

FOSSBilling includes the default Twig filters, plus the Intl Extra Extension and Markdown Extra Extension.

Common bundled filters include:

Filter	Description
`format_currency`	Format a number as currency, for example `{{ 29.99 \| format_currency('USD') }}`.
`format_date`	Format a date using the configured locale and date format.
`format_datetime`	Format a date and time using the configured locale and time zone.
`markdown_to_html`	Convert Markdown to HTML with FOSSBilling's safe CommonMark renderer.

FOSSBilling Custom Filters

Project-specific filters and functions are defined in these classes:

Translation & Localization

Filter	Description
`trans`	Translate a string using FOSSBilling's translation system.
`timeago`	Show how long ago a date was (e.g., "2 hours ago"). Accepts ISO 8601 format.
`daysleft`	Show days until a date. Accepts ISO 8601 format.
`period_title`	Display a translated period title (e.g., `1M` → "1 Month").
`ip_country_name`	Show the country name for an IP address.

URLs & Links

Filter	Description
`url`	Generate a URL for the current area, or pass `area: 'admin'` / `area: 'client'`.
`api_url`	Generate a URL for an API endpoint. Defaults to the current area; pass `role: 'admin'`, `role: 'client'`, or `role: 'guest'` when needed.

Assets & Resources

Filter	Description
`asset_url`	Get the URL for a theme asset.
`library_url`	Get the URL for the library folder.
`mod_asset_url`	Get the URL for a module asset. Use the asset path as the filtered value and the module name as the argument.
`script_tag`	Generate an HTML `<script>` tag.
`stylesheet_tag`	Generate an HTML `<link>` tag for CSS.

Utilities

Filter	Description
`file_size`	Convert bytes to a human-readable size (KB, MB, GB, etc.).
`hash`	Hash a value. Defaults to `xxh128`; pass another PHP-supported algorithm if needed.
`truncate`	Truncate a string to a maximum length.

FOSSBilling Custom Functions

Function	Description
`fb_api`	Refer to JavaScript Wrapper for documentation.
`fb_api_form`	Refer to JavaScript Wrapper for documentation.
`fb_api_link`	Refer to JavaScript Wrapper for documentation.
`render_widgets`	Render widgets registered for a slot.
`svg_sprite`	Render the current theme's SVG icon sprite when available.
`has_permission`	Check whether the logged-in admin has a module permission.

Usage Examples

{# Format currency #}
{{ 29.99 | format_currency('USD') }} {# $29.99 #}

{# Generate client and admin URLs #}
<a href="{{ 'invoice' | url }}">Invoices</a>
<a href="{{ 'client/manage' | url(area: 'admin') }}">Manage Client</a>

{# Generate API URLs #}
{{ 'profile/update' | api_url }}
{{ 'client/login' | api_url(role: 'guest') }}

{# Parse Markdown #}
{{ product.description | markdown_to_html }}

{# Time ago #}
{{ order.created_at | timeago }}  {# 2 hours ago #}

{# Theme and module assets #}
<link rel="stylesheet" href="{{ 'css/theme.css'|asset_url }}">
<script src="{{ 'js/widget.js'|mod_asset_url('Example') }}"></script>

{# API form handled by Api/API.js #}
<form action="{{ 'profile/update'|api_url }}" {{ fb_api_form({ message: 'Saved'|trans }) }}>
  <input type="text" name="first_name">
  <button type="submit">{{ 'Save'|trans }}</button>
</form>

{# API link with a confirmation modal #}
<a href="{{ 'client/delete'|api_url(query: { id: client.id }, role: 'admin') }}"
   {{ fb_api_link({ modal: { type: 'confirm', title: 'Are you sure?'|trans }, reload: true }) }}>
  {{ 'Delete'|trans }}
</a>

See JavaScript API Wrapper for the data-fb-api options and CSRF behavior.