> ## Documentation Index > Fetch the complete documentation index at: https://developers.telnyx.com/llms.txt > Use this file to discover all available pages before exploring further. # Play audio URL > Play an audio file on the call. If multiple play audio commands are issued consecutively, the audio files will be placed in a queue awaiting playback. *Notes:* - When `overlay` is enabled, `target_legs` is limited to `self`. - A customer cannot Play Audio with `overlay=true` unless there is a Play Audio with `overlay=false` actively playing. **Expected Webhooks:** - `call.playback.started` - `call.playback.ended` ## OpenAPI ````yaml https://telnyx-openapi-ng.s3.us-east-1.amazonaws.com/call-control-commands/playback-start.yml post /calls/{call_control_id}/actions/playback_start openapi: 3.1.0 info: title: Telnyx Call Control - Playback Start version: 2.0.0 description: API for starting audio playback. contact: email: support@telnyx.com servers: - url: https://api.telnyx.com/v2 security: - bearerAuth: [] tags: - name: Command description: Call control command operations - name: Callbacks description: Webhook callbacks for call events paths: /calls/{call_control_id}/actions/playback_start: post: tags: - Call Commands summary: Play audio URL description: > Play an audio file on the call. If multiple play audio commands are issued consecutively, the audio files will be placed in a queue awaiting playback. *Notes:* - When `overlay` is enabled, `target_legs` is limited to `self`. - A customer cannot Play Audio with `overlay=true` unless there is a Play Audio with `overlay=false` actively playing. **Expected Webhooks:** - `call.playback.started` - `call.playback.ended` operationId: StartCallPlayback parameters: - $ref: '#/components/parameters/CallControlId' requestBody: description: Play audio URL request required: true content: application/json: schema: $ref: '#/components/schemas/PlayAudioUrlRequest' responses: '200': $ref: '#/components/responses/CallControlCommandResponse' '422': $ref: '#/components/responses/UnprocessableEntityResponse' default: $ref: '#/components/responses/call-control_GenericErrorResponse' x-codeSamples: - lang: JavaScript source: >- import Telnyx from 'telnyx'; const client = new Telnyx({ apiKey: process.env['TELNYX_API_KEY'], // This is the default and can be omitted }); const response = await client.calls.actions.startPlayback('call_control_id'); console.log(response.data); - lang: Python source: |- import os from telnyx import Telnyx client = Telnyx( api_key=os.environ.get("TELNYX_API_KEY"), # This is the default and can be omitted ) response = client.calls.actions.start_playback( call_control_id="call_control_id", ) print(response.data) - lang: Go source: "package main\n\nimport (\n\t\"context\"\n\t\"fmt\"\n\n\t\"github.com/team-telnyx/telnyx-go\"\n\t\"github.com/team-telnyx/telnyx-go/option\"\n)\n\nfunc main() {\n\tclient := telnyx.NewClient(\n\t\toption.WithAPIKey(\"My API Key\"),\n\t)\n\tresponse, err := client.Calls.Actions.StartPlayback(\n\t\tcontext.TODO(),\n\t\t\"call_control_id\",\n\t\ttelnyx.CallActionStartPlaybackParams{},\n\t)\n\tif err != nil {\n\t\tpanic(err.Error())\n\t}\n\tfmt.Printf(\"%+v\\n\", response.Data)\n}\n" - lang: Java source: >- package com.telnyx.sdk.example; import com.telnyx.sdk.client.TelnyxClient; import com.telnyx.sdk.client.okhttp.TelnyxOkHttpClient; import com.telnyx.sdk.models.calls.actions.ActionStartPlaybackParams; import com.telnyx.sdk.models.calls.actions.ActionStartPlaybackResponse; public final class Main { private Main() {} public static void main(String[] args) { TelnyxClient client = TelnyxOkHttpClient.fromEnv(); ActionStartPlaybackResponse response = client.calls().actions().startPlayback("call_control_id"); } } - lang: Ruby source: |- require "telnyx" telnyx = Telnyx::Client.new(api_key: "My API Key") response = telnyx.calls.actions.start_playback("call_control_id") puts(response) - lang: CLI source: |- telnyx calls:actions start-playback \ --api-key 'My API Key' \ --call-control-id call_control_id components: parameters: CallControlId: name: call_control_id description: Unique identifier and token for controlling the call in: path required: true schema: type: string schemas: PlayAudioUrlRequest: type: object title: Play Audio URL Request properties: audio_url: type: string example: http://example.com/message.wav description: >- The URL of a file to be played back on the call. The URL can point to either a WAV or MP3 file. media_name and audio_url cannot be used together in one request. media_name: type: string example: my_media_uploaded_to_media_storage_api description: >- The media_name of a file to be played back on the call. The media_name must point to a file previously uploaded to api.telnyx.com/v2/media by the same user/organization. The file must either be a WAV or MP3 file. loop: $ref: '#/components/schemas/Loopcount' description: >- The number of times the audio file should be played. If supplied, the value must be an integer between 1 and 100, or the special string `infinity` for an endless loop. example: infinity default: 1 overlay: description: >- When enabled, audio will be mixed on top of any other audio that is actively being played back. Note that `overlay: true` will only work if there is another audio file already being played on the call. type: boolean example: true default: false stop: description: >- When specified, it stops the current audio being played. Specify `current` to stop the current audio being played, and to play the next file in the queue. Specify `all` to stop the current audio file being played and to also clear all audio files from the queue. type: string example: current target_legs: description: >- Specifies the leg or legs on which audio will be played. If supplied, the value must be either `self`, `opposite` or `both`. type: string default: self example: self cache_audio: description: >- Caches the audio file. Useful when playing the same audio file multiple times during the call. type: boolean default: true example: true audio_type: description: >- Specifies the type of audio provided in `audio_url` or `playback_content`. type: string enum: - mp3 - wav default: mp3 example: wav playback_content: description: >- Allows a user to provide base64 encoded mp3 or wav. Note: when using this parameter, `media_url` and `media_name` in the `playback_started` and `playback_ended` webhooks will be empty type: string example: SUQzAwAAAAADf1... client_state: description: >- Use this field to add state to every subsequent webhook. It must be a valid Base-64 encoded string. type: string example: aGF2ZSBhIG5pY2UgZGF5ID1d command_id: description: >- Use this field to avoid duplicate commands. Telnyx will ignore any command with the same `command_id` for the same `call_control_id`. type: string example: 891510ac-f3e4-11e8-af5b-de00688a4901 example: audio_url: http://www.example.com/sounds/greeting.wav loop: infinity overlay: true stop: current target_legs: self client_state: aGF2ZSBhIG5pY2UgZGF5ID1d command_id: 891510ac-f3e4-11e8-af5b-de00688a4901 Loopcount: oneOf: - type: string - type: integer CallControlCommandResult: type: object title: Call Control Command Result example: result: ok properties: result: type: string example: ok call-control_Errors: properties: errors: type: array items: $ref: '#/components/schemas/call-control_Error' call-control_Error: required: - code - title properties: code: type: string format: integer title: type: string detail: type: string source: type: object properties: pointer: description: JSON pointer (RFC6901) to the offending entity. type: string format: json-pointer parameter: description: Indicates which query parameter caused the error. type: string meta: type: object responses: CallControlCommandResponse: description: Successful response upon making a call control command. content: application/json: schema: type: object title: Call Control Command Response properties: data: $ref: '#/components/schemas/CallControlCommandResult' UnprocessableEntityResponse: description: >- Unprocessable entity. The request was well-formed but could not be processed due to semantic errors. This includes validation errors, invalid parameter values, call state errors, conference errors, queue errors, recording/transcription errors, and business logic violations. content: application/json: schema: $ref: '#/components/schemas/call-control_Errors' examples: missing_required_parameter: summary: Missing required parameter value: errors: - code: '10004' title: Missing required parameter detail: The 'to' parameter is required and cannot be blank. source: pointer: /to invalid_call_control_id: summary: Invalid call control ID value: errors: - code: '90015' title: Invalid Call Control ID detail: The call_control_id provided was not valid. source: pointer: /call_control_id call_already_ended: summary: Call has already ended value: errors: - code: '90018' title: Call has already ended detail: This call is no longer active and can't receive commands. call_not_answered: summary: Call not answered yet value: errors: - code: '90034' title: Call not answered yet detail: >- This call can't receive this command because it has not been answered yet. cannot_record_before_audio_started: summary: Cannot record before audio started value: errors: - code: '90020' title: Call recording triggered before audio started detail: >- Call recording cannot be started until audio has commenced on the call. transcription_already_active: summary: Transcription already active value: errors: - code: '90054' title: Call transcription is already in progress detail: Call transcription can not be started more than once. ai_assistant_already_active: summary: AI Assistant already active value: errors: - code: '90061' title: AI Assistant is already in progress detail: AI Assistant cannot be started more than once. conference_already_ended: summary: Conference has already ended value: errors: - code: '90019' title: Conference has already ended detail: >- This conference is no longer active and can't receive commands. conference_name_conflict: summary: Conference name conflict value: errors: - code: '90033' title: Unable to execute command detail: Conference with given name already exists and it's active. max_participants_reached: summary: Maximum participants reached value: errors: - code: '90032' title: Maximum number of participants reached detail: >- The maximum allowed value of `max_participants` has been reached at 100. queue_full: summary: Queue is full value: errors: - code: '90036' title: Queue full detail: The 'support' queue is full and can't accept more calls. call_already_in_queue: summary: Call already in queue value: errors: - code: '90038' title: Call already in queue detail: Call can't be added to a queue it's already in. invalid_connection_id: summary: Invalid connection ID value: errors: - code: '10015' title: Invalid value for connection_id (Call Control App ID) detail: >- The requested connection_id (Call Control App ID) is either invalid or does not exist. Only Call Control Apps with valid webhook URL are accepted. source: pointer: /connection_id invalid_phone_number_format: summary: Invalid phone number format value: errors: - code: '10016' title: Phone number must be in +E164 format detail: The 'to' parameter must be in E164 format. source: pointer: /to srtp_not_supported_for_pstn: summary: SRTP not supported for PSTN calls value: errors: - source: pointer: /media_encryption title: Media encryption not supported for PSTN calls detail: SRTP media encryption is not supported for PSTN calls. code: '10011' fork_not_found: summary: Call is not forked value: errors: - code: '90031' title: Call is not currently forked detail: >- Can't stop forking, because the call isn't currently forked. media_streaming_used: summary: Media streaming in use value: errors: - code: '90045' title: Media Streaming is used detail: This command can't be issued when media streaming is used. invalid_enumerated_value: summary: Invalid enumerated value value: errors: - code: '10032' title: Invalid enumerated value detail: 'The value must be one of: dual, single.' source: pointer: /record_channels value_outside_range: summary: Value outside of range value: errors: - code: '10033' title: Value outside of range detail: The value is outside of allowed range 1 to 5000 source: pointer: /max_participants call-control_GenericErrorResponse: description: Unexpected error content: application/json: schema: $ref: '#/components/schemas/call-control_Errors' securitySchemes: bearerAuth: scheme: bearer type: http ````