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The <Play> verb plays an audio file, which SignalWire fetches from the URL you configured, back to the caller.

An example of an audio file set to loop 15 times:

<?xml version="1.0" encoding="UTF-8"?>
<Play loop="15"></Play>

An example which plays an RTMP stream into the call:

<?xml version="1.0" encoding="UTF-8"?>
<Play loop="15">rtmp://</Play>

Verb Attributes

loop optionalThe loop attribute determines how many times an audio file is played. If no loop is specified, it will default to 1, which means the audio file will only play once. If loop is set to '0', <Play> will continue looping until the call has ended.
digits optionalThe digits attribute allows you to play DTMF tones throughout a call. If pauses are required in between your DTMF tones, the character w can be used. w adds a pause of 0.5 seconds for each occurrence, so www would render a pause of 1.5 seconds.

Note that this attribute simply plays tones into a call. To enter an extension when making a call, use the sendDigits attribute for the noun <Number> of the verb <Dial>.


The noun of an XML verb is nested within the verb upon which the verb acts. <Play> has the following noun:

plain textThe URL of the audio file that will be played to the caller. Supported protocols are HTTP and RTMP

MIME Types

The following are the MIME types supported by SignalWire:

audio/mpegmpeg layer 3 audio
audio/wavwav format audio
audio/wavewav format audio
audio/x-wavwav format audio
audio/aiffaudio interchange file format
audio/x-aifcaudio interchange file format
audio/x-aiffaudio interchange file format
audio/x-gsmGSM audio format
audio/gsmGSM audio format
audio/ulawμ-law audio format


No other verbs can be nested within <Play>. However, <Play> can be nested within <Gather>. In this case, the verb attribute digits is not supported.


Play a Simple Audio File

const { RestClient } = require("@signalwire/compatibility-api");
const response = new RestClient.LaML.VoiceResponse();"");

The simplest case for <Play>: SignalWire downloads the specified audio file and plays it to the caller.

Use DTMF Tones in Calls

<?xml version="1.0" encoding="UTF-8"?>
<Play digits="wwwww9"></Play>

As described in the attributes section, the character w produces a 0.5 second pause. In this example, SignalWire will wait 2.5 seconds before playing the digit '9'.

Notes on Usage

  • Audio files that are longer than 40 minutes should be split into smaller files, as it may result in a dropped call.
  • Since it takes some time to download and cache files from your server, slight delays may occur the first time an audio file is played. In this case, SignalWire may play a tone during download.
  • SignalWire attempts to cache files only when allowed by HTTP headers (ETag and Last-Modified). Always check for a new version of the file with a response of Cache-Control: no-cache. This enables your server to respond with a new version, or with a '304 Not Modified', which tells SignalWire to use the cached version.
  • The degradation that occurs when transcoding high bitrate, lossy encoded files, such as 128kbps MP3 files, can take a long time, resulting in audio that sounds worse than those in lossless 8kbps formats.
  • SignalWire transcodes all audio files into a format that is identifiable by the telephone network. Telephones typically do not support high bitrate audio, so playback results in lower-quality audio.