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Configuring Programmable Fax Applications
Configuring Programmable Fax Applications
Learn how to configure your settings in order to send and receive faxes via API.
Dillin avatar
Written by Dillin
Updated over a week ago

This article describes the in-depth setup of Programmable Fax / Applications on your Mission Control Portal in order to send and receive faxes via our API.

Video Walk-through for Programmable Fax

How to receive a fax

How to send a fax

Configuration of Programmable Fax

The Programmable Fax applications section is located on the left hand side of the portal.

Click on this button below and it will directly get you to the Programmable Fax Applications page.

Step By Step Guide to Programmable Fax

There are 3 sections which you can configure: App Info, Inbound Settings & Outbound Settings.

App Info

  • App Name: Click on " Create your first application" and assign a name to this application to better manage the application.

  • Send a webhook to the URL: You will need to input a URL where all the webhook events will be sent. Also, you can setup a fail-over URL. If two consecutive delivery attempts to the primary URL fail, Telnyx will attempt delivery to this URL. NOTE: Must include a scheme such as 'https'.

  • Custom webhook retry delay (seconds): In this field, you will need to specify a delay in seconds for Telnyx to wait before retrying an unsuccessful webhook delivery attempt. If not set, Telnyx will retry immediately.

  • AnchorSiteĀ® Selection: "Latency" directs Telnyx to route media through the site with the lowest round-trip time to the user's connection. Telnyx calculates this time using ICMP ping messages. This can be disabled by specifying a site to handle all media.

Inbound Settings

  • SIP subdomain: Specifies a subdomain that can be used to receive calls to a Connection, in the same way a phone number is used, from a SIP endpoint. Example: the subdomain "" can be called from any SIP endpoint by using the SIP URI "" where the user part can be any alphanumeric value. Please note TLS encrypted calls are not allowed for subdomain calls.

  • SIP subdomain receive settings: In this field, either you setup your receive SIP subdomain connection from anyone or only connections.

  • Inbound Channel Limit: You can limit the total number of inbound calls to phone numbers associated with this connection.

Outbound Settings

  • Outbound Voice Profile: Assign your application to an outbound voice profile to allow outbound faxes from your application.

  • Outbound Channel Limit: You can limit the total number of outbound calls to phone numbers associated with this connection.

Notes on Programmable Fax

Don't forget to assign the fax application to your purchased numbers, in order to receive faxes to your application and for Telnyx to send the webhook events when faxes are received to our network.

Check out our fax API quick-start guide here and more detail on the API endpoints in our developer center.

Can't find what you're looking for? Click the chat bubble at your lower right-hand corner and talk to the support team!

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