Pax Fax

License: GNU Affero General Public License v3

Version: 1.1.0
Release date: 2023-3-22

View in Nextcloud App Store
Git repository

Pax Faxβ„’ is a Nextcloud application that allows sending and receiving faxes in Nextcloud.

A account and a real fax number acquired from Phaxio are needed.

Main features:

  • πŸš€ Multiple documents can be sent in one fax call (up to 20 separate files with a cumulative size of up to 20 MB).
  • πŸ“  A fax can be sent to multiple fax numbers at once (up to 15 different fax numbers).
  • πŸ“„ Users can send as fax any document in any of the following formats: pdf, doc, docx, odt, jpeg/jpg, png, tiff/tif, txt, html.
  • πŸ“° All incoming faxes are received as pdf documents and stored in a Nextcloud folder.
  • πŸ“§ Users receive notifications and (optionally) emails when new faxes arrive.
  • πŸ” All the sent and received faxes are stored in specific Nextcloud folders, so that they can be searched by caller/callee phone number or date.
  • πŸ’» When they want to send a fax, users can upload files from their computer or choose them directly from Nextcloud.
  • πŸ” Incoming fax requests are checked for authenticity and integrity by verifying Phaxio’s signature.
  • πŸ’΅ Current Phaxio balance can be always checked by pressing a button on the left panel.
  • πŸ’° The only ongoing cost is $2 per month for a fax number located in USA or Canada, in a city chosen by the user. No contracts.
  • πŸ’Έ Straightforward pricing: $0.07 per sent/received page for faxes to/from USA and Canada and $0.1 per sent/received page for faxes to/from other countries.

Double Bastion is not affiliated with Phaxio.

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Send uploaded file as fax

Preview received fax

Choose file from Nextcloud

Choose multiple files from local computer and Nextcloud

View list of received faxes

View list of sent faxes


Pax Fax works with all major browsers.

Programming Languages

Pax Fax only uses PHP, SQL, jQuery, CSS and HTML. This means it’s robust, efficient, light-weight and easy to maintain and debug.

Minimum Requirements

  • Nextcloud 22+ has to be installed and properly configured, preferably by following the Install Nextcloud chapter in our guide.
  • A account and a fax number associated with it.
  • The libcurl PHP library has to be installed on the server.

To enable email notifications for every received fax, the sendmail utility (/usr/sbin/sendmail on Debian Linux), has to be present on the server. sendmail is a binary which gets installed when Postfix is installed. Also, the web server user (www-data) has to be allowed to send emails from command line (by specifying authorized_submit_users = www-data in /etc/postfix/ for Postfix on Debian).


This chapter of our Complete Guide to a Complete Linux Server presents in detail how to install and use this application.

Pax Fax is a component of RED Scarf Suite. It can be installed and used alone, but if you want to install all the components of RED Scarf Suite, you can follow our complete guide.


The GitHub Pax Fax repository is just a pointer to the official Pax Fax repository. We don’t use GitHub for developing Pax Fax because GitHub is owned by one of the companies that proved their disrespect for digital freedom over the years and because centralized services create autonomy and privacy issues, in spite of all the benefits.

If you want to contribute code to this project, please submit this form, mentioning your intended changes. We’ll send you the credentials needed to push code to the “contrib” branch of the official repository. After we review the changes, we can include them in the project.

Please post any bugs that are not security related, or feature requests, on the issue tracker. If you notice bugs related to security, don’t post them on the issue tracker; instead, send them to manager [at] doublebastion [dot] com .


Pax Fax as a whole is licensed under the GNU Affero General Public License Version 3. If you use Pax Fax or distribute it in modified or unmodified form, you will need to comply with the terms of the GNU Affero General Public License Version 3.

Pax Fax includes libraries licensed under different free software licenses. These libraries contain their respective original copyright notices.

If you have any questions, you can send them to: