TeXML Translator

TeXML is an XML based data structure used by Telnyx to build quick applications to be associated with your Telnyx phone numbers. When a call comes into one of your Telnyx Numbers, Telnyx makes an HTTP request to the URL endpoint you configured for that number. The endpoint will contain instructions telling Telnyx what to do next with the call.

Responses to the HTTP request are in an XML format that we call TeXML. TeXML allows you to specify instructions in your file using simple commands called verbs. TeXML Translator starts at the top of your TeXML file and executes your TeXML commands sequentially in the order they are arranged in the file.

How TeXML Translator works

Check out our TeXML Setup Guide to get started on a simple TeXML text-to-speech application.

When a call is received by one of your Telnyx phone numbers, Telnyx lookup the URL endpoint you configured for that number and make an HTTP request to it. The URL endpoint then responds to the request with a TeXML file that instructs what to do next in the call. TeXML files have a standard .xml file extension.

Telnyx will read the instructions in the TeXML file, from top to bottom, and execute all the verbs/commands in order.

Outbound calls started via the TeXML Translator work the same way. When you start an outbound call, you also pass a link to a TeXML file. Telnyx will make a request to this file to determine how it should proceed with the call.

While a single TeXML document is executed at a time, many documents can be linked together and generated dynamically to create complex applications to fit any need.

TeXML Syntax

TeXML Translator is XML-based and consists of the following elements:

• <Response> element -- tag defining the body of the TeXML document
• verb -- an XML tag denoting the action that you want Telnyx to take
• noun -- the item for the action specified in the associated verb

Here is a simple TeXML file containing an example of a verb and noun used together:

<?xml version="1.0" encoding="UTF-8"?>

<!-- TeXML files must contain the Response element -->
<Response>
 <!-- Say and Dial are Verbs -->
    <Say>Thank you for calling Telnyx. Please hold.</Say>
    <Dial>
   <!-- Number is a Dial Noun -->
        <Number>+13129457420</Number>
    </Dial>
</Response>

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Response

The baseline of TeXML files is the <Response> tag.

All verbs in a TeXML file must be placed within a single parent <Response> element, and each file can only have a single one.

Verbs

A verb identifies the action to take.

When using Verbs one instruction must completed before the next one is executed. Verbs may have optional TeXML attributes that override the flow of execution, allowing you customize the verb behavior.

All verbs are case sensitive, so <Dial> and <dial> are not interchangeable.

Voice Verbs

The following verbs cause the specified action to take place during the call:

Nouns

A noun is what the verb uses to complete an action and is placed inside a verb element. A noun can be the text that is read in a call or other TeXML elements that represent the action, such as Number to dial or a SIP URI to transfer the call to.

<?xml version="1.0" encoding="UTF-8"?>
<Response>
 <Dial>
      <Sip>sip:agent1@contactcenter.com</Sip>
 </Dial>
</Response>

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Each verb has its own set of nouns. See the documentation for a specific verb for more details.

Additional Request Parameters

Each time Telnyx makes a request to your application to fetch new TeXML, additional parameters with information about the call will be sent with the request to your URL.

PARAMETER	DESCRIPTION
CallSid	A unique identifier for this call, generated by Telnyx.
From	The phone number of the party that initiated the call. Phone numbers are formatted with a '+' and country code, e.g. +16175551212 (E.164 format).
To	The phone number of the called party. Phone numbers are formatted with a '+' and country code, e.g. +16175551212 (E.164 format).

Data Formats

Dates and Times

All dates and times in requests to and from TeXML files follow Telnyx API conventions: UTC, and presented in RFC 2822 format.

Phone Numbers

All numbers in requests to or from TeXML files follow Telnyx API conventions: E.164 format. Numbers in this format start with a plus sign ("+") and the country code.

SIP URIs follow Telnyx SIP Trunking and SIP Credentials conventions: sip:telnyxagent@sip.telnyx.com

Dial

The <Dial> verb transfers an existing call to another destination. <Dial> will end this new call if: the called party does not answer, the number does not exist, or Telnyx receives a busy signal.

Verb Attributes

ATTRIBUTE	DESCRIPTION	OPTIONS	DEFAULT
action	Optional URL where TeXML will make a request to when the <Dial> call ends to retrieve a new set of TeXML instructions to continue the call flow.
method	HTTP request type used to retrieve the next set of instructions.	GET, POST	POST
callerId	Caller ID that must be a valid E.164 format number.
hangupOnStar	The hangupOnStar attribute lets the initial caller hang up on the called party by pressing the '*' key on their phone.	true, false	false
record	The record attribute lets you record both legs of a call within the associated <Dial> verb. Recordings are available in two options: mono-channel or dual-channel.	do-not-record, record-from-answer, record-from-ringing, record-from-answer-dual, record-from-ringing-dual	do-not-record
recordingStatusCallback	Optional URL that tells Telnyx where to make its GET or POST request when the recording is available.
recordingStatusCallbackMethod	HTTP request type used for recordingStatusCallBack.	GET, POST	POST
recordingStatusCallbackEvent	The recording events for which Telnyx should a webhook on. Multiple events are separated by a space.	in-progress, completed, absent	completed
timeLimit	Sets the maximum duration in seconds of the call created by <Dial>.	60 - 14,400	14,400 (4 hours)
timeout	Sets the maximum time in seconds that Telnyx will wait for the dialed party to answer.	5 - 120	30

Nouns

NOUN	DESCRIPTION	OPTIONAL ATTRIBUTES
<Number>	E.164 phone number.	method, sendDigits, statusCallback, statusCallbackEvent, statusCallbackMethod
<Sip>	SIP URI.	method, password, statusCallback, statusCallbackEvent, statusCallbackMethod, url, username

Send custom headers by appending them to the SIP URI -- just as you'd pass headers in a URI over HTTP. For example:

<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Dial>
        <Sip>
            sip:jack@example.com?x-mycustomheader=foo&amp;x-myotherheader=bar
        </Sip>
    </Dial>
</Response>

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Noun Attributes

<Number> and <Sip> Attributes

ATTRIBUTE	DESCRIPTION	OPTIONS	DEFAULT
statusCallback	A URL for Telnyx to send webhook requests to on each event specified in the statusCallbackEvent attribute for outbound calls only. Inbound Status Callback events can be configured for TeXML the connection settings in the Mission Control Portal.
statusCallbackEvent	The call events for which Telnyx should a webhook on. Multiple events are separated by a space.	initiated, ringing, answered, completed	completed
statusCallbackMethod	HTTP request type Telnyx should use when requesting the statusCallback URL.	GET, POST	POST
url	Optional URL to another TeXML document that can contain <Gather> and <Hangup> verbs so that the called party can chose to take an action on the incoming call before the two parties are connected. The callee will continue to hear ringback while the url document is executed.
method	HTTP request type used for url.	GET, POST	POST

<Number> Only Attributes

<Sip> Only Attributes

Status Callback HTTP Attributes

The attributes contained in the statusCallback request to your URL.

ATTRIBUTE	DESCRIPTION
CallSid	A unique identifier for this call, generated by Telnyx.
ParentCallSid	A unique identifier for the parent call.
CallStatus	A descriptive status for the call. The value is one of initiated, ringing, in-progress, completed, busy or canceled.
Timestamp	The timestamp when the event was fired, given as UTC in RFC 2822 format.
CallbackSource	A string that describes the source of the webhook. This is provided to help disambiguate why the webhook was made. On Status Callbacks, this value is always call-progress-events.
From	The outbound caller number.
To	The inbound callee number.

Simultaneous Dialing

You can use multiple <Number> and <Sip>nouns within a <Dial> verb to dial multiple phone numbers and SIP addresses at the same time. The first person to answer the call will be connected to the caller, while the rest of the call attempts are hung up:

<?xml version="1.0" encoding="UTF-8"?>
<Response>
  <Dial>
    <Number>+18775551212</Number>
    <Sip>sip:connection@sip.telnyx.com</Sip></Sip>
    <Number>+18771234567</Number>
  </Dial>
</Response>

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Examples

<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Dial action="/nextinstructions.php" callerId="+13120001234">+19999999999</Dial>
</Response>

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<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Dial action="/nextinstructions.php" callerId="+13120001234">
      <Number statusCallback="https://foo.com/my_call_stats" statusCallbackEvent="initiated ringing answered completed">+19999999999</Number>
    </Dial>
</Response>

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<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Dial action="/nextinstructions.php" callerId="+13120001234" hangupOnStar="true">
      <Sip statusCallback="https://foo.com/my_sip_call_stats" statusCallbackEvent="initiated">sip:connection@sip.telnyx.com</Sip>
    </Dial>
</Response>

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Initiate a TeXML Call using the Telnyx API

It is possible to initiate a TeXML call using a Telnyx API endpoint. Simply specify the connection_id (application_id) for the connection you want to use for the call. Telnyx will request TeXML from the XML Request URL configured for that connection in the Telnyx Mission Control Portal.

PARAMETER	DESCRIPTION	OPTIONS	DEFAULT
FallbackUrl	A failover URL for which Telnyx will retrieve the TeXML call instructions if the Url is not responding.
From	The phone number of the party that initiated the call. Phone numbers are formatted with a '+' and country code, e.g. +16175551212 (E.164 format).
StatusCallback	URL destination for Telnyx to send status callback events to for the call.
StatusCallbackMethod	HTTP request type used for StatusCallBack.	GET,POST	POST
To	The phone number of the called party. Phone numbers are formatted with a '+' and country code, e.g. +16175551212 (E.164 format).
Url	The URL from which Telnyx will retrieve the TeXML call instructions.
UrlMethod	HTTP request type used for Url.	GET,POST	Inherited from TeXML Application setting.

curl -X POST https://api.telnyx.com/v2/texml/calls/{connection_id} \
--data-urlencode "To=+13121230000" \
--data-urlencode "From=+13120001234" \
--data-urlencode "Url=https://www.example.com/texml.xml" \
--data-urlencode "StatusCallback=https://www.example.com/statuscallback-listener" \
--header "Authorization: Bearer APIAuthKey_fromPortal"

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Conference

The <Dial> verb's <Conference> noun allows you to connect to a conference room. Much like how the <Number> noun allows you to connect to another phone number, the <Conference> noun allows you to connect to a named conference room and talk with the other callers who have also connected to that room. Conference is commonly used as a container for calls when implementing hold, transfer, and barge. If the specified conference name does not exist, a new conference will be created. More <Conference> attributes are coming soon.

Verb Attributes

Example

<?xml version="1.0" encoding="UTF-8"?>
<Response>
  <Dial>
    <Conference>Room 1234</Conference>
  </Dial>
</Response>

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Gather

The <Gather> verb collects DTMF tones during a call. <Say> can be nested within <Gather> to create an interactive IVR with text-to-speech.

Verb Attributes

Nouns

Example

<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Gather action="/processdtmf.php" finishOnKey="*" timeout="20">
        <Say>Please press 1 for sales, or 2 for support. Press * to exit the menu.</Say>
    </Gather>
   <Say>We did not receive any input. Goodbye!</Say>
</Response>

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Hangup

The <Hangup> verb ends the current call. There are no attributes associated with <Hangup> and no nouns can be nested within it.

Example

<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Say>Support line is closed. Please try again tomorrow.</Say>
    <Hangup />
</Response>

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Pause

The <Pause> verb waits silently for a specified number of seconds or one second by default. No nouns can be nested within <Pause> and a self-closing tag must be used.

Verb Attributes

Example

<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Pause length="5"/>
</Response>

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Play

The <Play> verb plays an MP3 or WAV audio file, that Telnyx fetches from the URL you configure, back to the caller.

<Play> can be used independently as a verb or nested within <Gather> as a noun to play an audio file while waiting for DTMF tones.

Verb Attributes

Example

<?xml version="1.0" encoding="UTF-8"?>
<Response>
  <Gather action="/processdtmf.php">
    <Play loop="10">http://www.example.com/sounds/greeting.wav</Play>
  </Gather>
</Response>

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Record

The <Record> verb creates an audio file with the call audio. If a recordingStatusCallback, Telnyx will deliver the URL for the recording to that address once the call has ended. Recording URLs are valid for 10 minutes after the call has ended. All recordings are also available via the Telnyx Mission Control Portal.

Verb Attributes

Additional Action Parameters

recordingStatusCallback will be used to deliver the final URL and information on the call recording. If available TeXML will also send recording information along with the request to the action URL with the following parameters:

Example

<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Record action="/recordingfinish.php" recordingStatusCallBack="https://wwww.foo.com/recording-storage/" playBeep="true" finishOnKey="*9"/>
    <Say>
        You reached Telnyx Sales voicemail.
        Please leave a message after the beep.
        Press the pound key when finished.
    </Say>
</Response>

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Redirect

The <Redirect> verb transfers control of the current call to another TeXML application. This is useful to create a tree structure of TeXML files for different applications. No nouns can be nested within <Redirect>.

Verb Attributes

Example

<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Redirect>http://www.example.com/TeXML/redirect.xml</Redirect>
</Response>

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Reject

The <Reject> verb rejects a call to your Telnyx number. It is effectively an exit statement from the current document, as there is no way to return to any instructions listed after the <Reject> verb. If placed as the very first verb in an incoming call, <Reject> will prevent the call from being answered and will incur no cost. If placed elsewhere in the call, the call will hang up but will be charged up to that point.

You can't nest any verbs within <Reject> and you can't nest <Reject> in any other verbs.

Verb Attributes

Example

<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Reject />
</Response>

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Say

The <Say> verb speaks the text specified back to the caller enabling text to speech for any application.

Verb Attributes

Example

<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Say voice="alice">This is a premium Amazon Polly text-to-speech message!</Say>
</Response>

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