Upland InterFAX affords developers the opportunity to register and test our fax services for free, allowing developers time to test their integration with InterFAX throughout the development process.

A developer account:

  1. Is completely free of charge, and;
  2. Has no limit on the length of time it is available to you.

(for other common questions regarding developer accounts, please visit our developer FAQ).

Registration process

Developers may self-register using our online web form – here.
Simply chose a unique Username and Password, then add your own details in order to get started.


When setting up an InterFAX developer account, InterFAX enforces some limitations on the account, in order to allow a free service for testing. These limitations are:

  • By destination: Developer accounts are limited to sending to a single destination fax number and are provided with simulated numbers for testing purposes, which will mimic the behaviour of regular fax lines. Developers may specify their own single fax number for testing by contacting our developer support
  • By total cost: a developer account is issued with a certain amount of free credits for sending faxes. The cost of faxes sent will be deducted from these credits until they run out. Once depleted, the developer will need to contact our developer support to add more credits to their account.

Sending faxes with your developer account

Sending faxes using the Test Simulator

InterFAX provides dummy numbers for testing purposes, in order to demonstrate the transmission and handling of faxes within the system. While these faxes are not sent to a real fax number, the user experience in the InterFAX system will demonstrate how actual faxes are processed and completed, both successfully and on failure.

To send a fax to a dummy number, simply submit the fax to a number format as +999-9999-[result code]. The [result code] should be replaced with the result code that you would like to simulate within InterFAX (the result code should be one of InterFAX’s fax transmission status codes).

Please note:

1. That the [result code] cannot be longer than 4 digits.

For example:

  • In order to experience a fax that results in success, submit the fax to number +999-9999-0.
  • In order to experience a fax that results in failure, due to a busy signal, submit the fax to number +999-9999-6017

2. Users in a ‘Developer’ account cannot send faxes to the “Dummy numbers” by email (see more information here: https://www.interfax.net/en/cphelp/sending-faxes/email-to-fax).

Designating a fax number for testing

Developers may specify their own single destination fax number (their office fax machine, for example), rather than the simulated test numbers, by contacting our developer support team.

When sending a fax to a designated number, you should format the fax number according to the InterFAX number formatting instructions (for example, +1 212 999 8888).

You can view your designated fax number online through our control panel under “My Settings” > “Developer Options”.

View sent faxes

You can view and manage your sent faxes online through our control panel under “Sent Items”.

Sending faxes to other numbers

While using a developer account, you are limited to sending faxes to either the designated fax number or the InterFAX dummy numbers. If you submit a fax to a number that is not your designated fax number or one of the simulated numbers, the request to submit the fax will fail with status code -111 (see web service status codes).