Customizing FOSSBilling
Customizing Email Templates

Email Templates

Customizing email templates

Finding them in the administrator panel

First, navigate to the email settings in your FOSSBilling administrator panel.

  1. Click on Configuration from the navbar and then go to Settings
  2. Click on the Email option.

At this point, you should see a table with a list of all email templates in your FOSSBilling instance. The table lists the subject of the template, what extension it is used in, the email code, and if it is enabled. If you are missing any email templates, use the Generate templates button at the bottom of the page to re-generate any missing email templates.

Editing an email template

Click on the edit button on any email template to edit it. You should then be presented with a screen similar to this: Editing an email template Email templates are processed via twig (opens in a new tab), which allows for them to take advantage of variables and filters to provide a more flexible email template system. You may find a list of available filters and functions on the Twig Filters & Functions (opens in a new tab) page.

In the following example, we will edit the test email template (mod_email_test). If you haven't already, configured your system email settings and and use the Send test email to staff members button to verify it is functional.

By default, the mod_email_test will be created with the following: Subject: [{{ }}] FOSSBilling Email Test Content:

{% apply markdown %}
Hi {{ }},

If you are reading this email, FOSSBilling is **configured properly** 
and is **able to send emails**.

{{ guest.system_company.signature }}

{% endapply %}

This is applying the markdown filter to convert all of the text you see into HTML, however you may also simply write the email template using HTML, which is what we will cover in this example.

Here's an example of a very basic HTML email template: Subject: [{{ }}] FOSSBilling Email Test


<!DOCTYPE html>
	<meta charset="utf-8">
	<style type="text/css">
		body {
			font-family: Arial, sans-serif;
			font-size: 14px;
			color: #333333;

		h1 {
			font-size: 24px;
			font-weight: bold;
			margin: 0 0 20px;

		p {
			margin: 0 0 10px;

		strong {
			font-weight: bold;

		.signature {
			font-style: italic;
			color: #999999;
			margin-top: 20px;
			border-top: 1px solid #cccccc;
			padding-top: 10px;
	<h1>Test email from [{{ }}]</h1>
	<p>Hi {{ }},</p>
	<p>If you are reading this email, FOSSBilling is <strong>configured properly</strong> and is <strong>able to send emails</strong>.</p>
	<p class="signature">{{ guest.system_company.signature }}</p>

This example code generates a very basic email template, however it includes some simple styling and results in an email that is visually more appealing to look at. Here are both email templates, generated using the preview button: How the default email template looks How the customized email template looks


  • Variables sent to email templates will not be known until an email template is sent at least once, at which point the preview button becomes enabled and the Variables tab will then have the variables and data from the last email that was sent.
  • HTML support from different email clients varies

Where are they stored?

When a module is first installed, the email templates are loaded from the html_email directory inside of each module. After that, though, they are stored inside the the email_template table in your FOSSBilling database. The email templates are all run through twig to allow usage of variables and filters.

You can find an example of the email templates in our example module (opens in a new tab).