WhatsApp — message/sendAudio

When to Use

Personalised voice messages: A sales workflow sends a personalised voice recording from an account manager to a high-value lead, creating a human connection that text cannot replicate.
Recorded announcements: An HR workflow sends a recorded CEO announcement about a company milestone to all employee WhatsApp numbers simultaneously.
Language-matched support: A multilingual support workflow sends pre-recorded audio explanations in the customer's language when a complex technical issue is better explained verbally.
Podcast and content delivery: A media platform sends episode audio clips to subscribers who opted in to WhatsApp previews as a way to drive full-episode listens.
Accessibility support: A government service workflow sends audio versions of important notices to users who indicated a preference for audio over written communication.

Configuration

Connection

Field	Required	Description
`accessToken`	Required	Permanent System User access token. Store in BizFirst Credentials Manager.
`phoneNumberId`	Required	Numeric string ID of the sending WhatsApp Business phone number.
`apiVersion`	Optional	Meta Graph API version. Defaults to `v18.0`.

Operation

Field	Required	Description
`to`	Required	Recipient's phone number with country code, no + prefix (e.g. `14155552671`).
`mediaUrl`	Required*	Publicly accessible HTTPS URL to the audio file. Supported formats: AAC, MP4 (audio only), MPEG, AMR, OGG (OPUS codec only). Maximum size: 16 MB. Audio does not support captions.
`mediaId`	Required*	ID of a previously uploaded audio file from `media/upload`. Use instead of `mediaUrl` for repeated sends or private files.

* Provide either mediaUrl or mediaId — exactly one is required. Audio messages do not support captions.

OGG Opus for voice messages: Audio sent as OGG with the OPUS codec displays as a voice message waveform in WhatsApp (with a microphone icon), which recipients perceive as more personal than a regular audio file. Use this format when simulating a voice message experience.

Sample Configuration

{
  "resource": "message",
  "operation": "sendAudio",
  "accessToken": "{{ $credentials.whatsAppToken }}",
  "phoneNumberId": "123456789012345",
  "to": "{{ $input.recipientPhone }}",
  "mediaUrl": "https://cdn.example.com/audio/announcements/{{ $input.announcementId }}.ogg"
}

Validation Errors

Error	Cause
`accessToken is required`	The `accessToken` field is empty.
`phoneNumberId is required`	The `phoneNumberId` field is empty.
`to is required`	The `to` field is empty.
`Either mediaId or mediaUrl is required`	Both fields are empty. Provide exactly one.
`131053` (Meta)	Audio download failed — URL inaccessible.
`131052` (Meta)	Unsupported audio codec or file exceeds 16 MB.
`131047` (Meta)	24-hour window expired. Audio cannot be sent via templates; use a text-based template with a link instead.

Output

Success Port

Field	Type	Description
`messageId`	string	Unique WhatsApp message ID (wamid).
`phoneNumberId`	string	The sending phone number ID.
`to`	string	The recipient phone number.
`status`	string	`"sent"` on success.
`errorCode`	string	Empty on success.
`errorMessage`	string	Empty on success.
`rawResponse`	string	Full raw JSON from the Meta API.

Error Port

Field	Type	Description
`status`	string	`"failed"` or `"error"`.
`errorCode`	string	Meta error code or BizFirst validation code.
`errorMessage`	string	Human-readable error description.
`rawResponse`	string	Raw API error response.

Sample Output

{
  "messageId": "wamid.HBgLMTQxNTU1NTI2NzEVAgARGBIxRTI4QUY0NjhFMEI4NDCAA",
  "phoneNumberId": "123456789012345",
  "to": "14155552671",
  "status": "sent",
  "errorCode": null,
  "errorMessage": null,
  "rawResponse": "{\"messaging_product\":\"whatsapp\",\"contacts\":[{\"input\":\"14155552671\",\"wa_id\":\"14155552671\"}],\"messages\":[{\"id\":\"wamid.HBgLMTQxNTU1NTI2NzEVAgARGBIxRTI4QUY0NjhFMEI4NDCAA\"}]}"
}

Expression Reference

Value	Expression	Notes
Message ID	`{{ $output.sendAudio.messageId }}`	Store to react to or delete the audio message later.
Recipient	`{{ $output.sendAudio.to }}`	For delivery confirmation logging.
Status	`{{ $output.sendAudio.status }}`	Branch on `"sent"` vs `"failed"`.
Error detail	`{{ $output.sendAudio.errorMessage }}`	Log on the error port for diagnostics.

Node Policies & GuardRails

Policy Area	Recommendation
Credential storage	Store the access token in BizFirst Credentials Manager. Never inline in configuration.
Format compatibility	Use OGG (Opus codec) for voice-note style delivery, or AAC for compatibility. MP3 is not supported by the WhatsApp Cloud API. Convert in a Function node if needed.
No captions	Audio messages do not support captions. If contextual text is needed, send a `message/sendText` immediately before or after the audio.
File size	Maximum 16 MB. Keep voice recordings concise. For longer content, split into multiple clips or host on a podcast platform and send a link.
24-hour window	Audio is a free-form message type. Outside the customer service window, use a text or document template to re-engage before sending audio.
Privacy	Do not send audio containing personally identifiable information about third parties without their consent. Audio messages may be forwarded by recipients.

Examples

Personalised Voice Greeting from Account Manager

{
  "resource": "message",
  "operation": "sendAudio",
  "accessToken": "{{ $credentials.whatsAppToken }}",
  "phoneNumberId": "123456789012345",
  "to": "{{ $input.clientPhone }}",
  "mediaId": "{{ $output.uploadGreeting.mediaId }}"
}

The account manager records a personalised 20-second welcome message. A Function node uploads it via media/upload and the mediaId is passed here. A follow-up message/sendText node sends a text summary with contact details.

Multilingual Support Audio

{
  "resource": "message",
  "operation": "sendAudio",
  "accessToken": "{{ $credentials.whatsAppToken }}",
  "phoneNumberId": "123456789012345",
  "to": "{{ $input.customerPhone }}",
  "mediaUrl": "https://cdn.example.com/support/{{ $input.language }}/{{ $input.topicCode }}.ogg"
}

A support workflow maps the customer's preferred language and issue category to a pre-recorded OGG audio clip. The URL pattern selects the correct file. The audio displays as a voice note waveform in WhatsApp.