A Programmable Fax API command is sent with a `fax_id`. The `fax_id` allows a user to communicate to Telnyx the `fax` the user wants to take an action on.

## Authenticating Your Fax Request

To send a Programmable Fax API command from your application, you must authenticate your request
by sending the Authorization header with a value of a key:secret pair. A key and secret can be retrieved from Auth in the Mission Control Portal under the tab Auth v2, or via the Telnyx API.

Credential Type|HTTP Header Format
--- |---
Key + Secret|Authorization: Basic base64("<key>:<secret>")

## Available Commands and their Expected Webhooks

Telnyx sends webhooks to update on the status of Programmable Fax. Webhooks will also be sent in response to requests to list and delete faxes.

<table class="small">
  <thead>
    <tr>
      <th class="nowrap" align="left">Command</th>
      <th class="nowrap" align="left">Associated Webhooks</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td><a href="/docs/api/v2/programmable-fax/Fax-Commands#ProgrammableFaxSend">Send a fax</a></td>
      <td><code>fax.queued</code><br>
      <code>fax.media.processed</code><br>
      <code>fax.sending.started</code><br>
      <code>fax.delivered</code><br>
      <code>fax.failed</code><br>
    </tr>
   </tbody>
</table>

### Response when sending command

When you send a Programmable Fax API Command, you will immediately receive an http response.
Responses include, but are not limited to:

HTTP Status Code|Message|Description
--- |--- |---
202|OK|The request succeeded.
403|Forbidden|The request was valid, however the user is not authorized to perform this action.|
404|Not Found|The requested resource could not be found.
422|Invalid Parameters|The request has invalid parameters.
429|Too many requests|There is a limit for outbound faxes of 2000 faxes being processed at the same time.

icon-fax

Programmable Fax | Telnyx Developer Center

Everything you need to know to start sending and receiving faxes using the Telnyx Programmable Fax API

Send and Receive Fax using the Telnyx API (V2)

Programmable Fax

Follow the steps to learn how to send a Programmable Fax API command with Telnyx. 

HTTP Status Code	Message	Description
202	OK	The request succeeded.
403	Forbidden	The request was valid, however the user is not authorized to perform this action.
404	Not Found	The requested resource could not be found.
422	Invalid Parameters	The request has invalid parameters.
429	Too many requests	There is a limit for outbound faxes of 2000 faxes being processed at the same time.

Sending Commands

Authenticating Your Fax Request

Available Commands and their Expected Webhooks

Response when sending command