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Answering Machine Detection (AMD) is a Wavix intelligence feature that analyzes the initial audio of an outbound call to determine if it was answered by a human or a machine. When an answering machine or voicemail greeting is detected, the Wavix platform automatically disconnects the call, saving your agents time and improving scale and efficiency.

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How AMD works

Wavix AMD analyzes the initial audio of a call to distinguish between a human response and a pre-recorded voicemail message. By identifying frequency patterns and audio characteristics, the platform can detect a machine even during Early Media playback (before the final answer signal). Wavix AMD also screens for automated network announcements played during Early Media—the period before a call is technically answered. By identifying these pre-answer signals and terminating the call immediately, the Wavix platform ensures that your resources are only dedicated to successful human connections.

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Activation levels

You can enable AMD at two different levels depending on your integration needs:

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1. Trunk level (Wavix portal & Wavix Embeddable)

Recommended for calls manually placed from your PBX or third-party systems connected via SIP, as well as features built using Wavix Embeddable. For these methods, AMD is controlled globally for the specific SIP trunk:
  1. Sign in to your Wavix account.
  2. In the top menu, click on Numbers & Trunks → Trunks.
  3. Select an existing SIP trunk to edit (or create a new one).
    Wavix Embeddable uses the SIP trunk configured during your application setup.
  4. Scroll down to the Trunk features section.
  5. Toggle Voicemail detection to ON.
  6. Click Save and close.
Once enabled, any outbound call made through this trunk—whether via a hardware phone or a Wavix Embeddable instance—that is answered by a machine will be automatically dropped.

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2. Call level (API only)

Recommended for programmable voice applications where you want granular control over which specific calls use AMD. This is currently supported exclusively by the Calls API.

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Via Calls API

To enable AMD for a specific call, set the voicemail_detection property to true in your POST /v1/calls request. 
curl -X POST "https://api.wavix.com/v1/calls" \
  -H "Authorization: Bearer <your_api_key_here>" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "13614157006",
    "to": "1234567890",
    "voicemail_detection": true
  }'

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AMD events and webhooks

To receive real-time notifications about AMD results, you can configure an on-call webhook. Wavix sends a POST callback to your designated URL whenever a call event occurs, such as when a call is answered and the AMD analysis is complete.

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Subscribe to call events

You can create a webhook using the Create a webhook endpoint: 
curl -X POST "https://api.wavix.com/v1/calls/webhooks" \
  -H "Authorization: Bearer <your_api_key_here>" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://your-app.com/webhooks/calls",
    "event_type": "on-call"
  }'

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The machine_detected event

When a call is answered and subsequently ends, Wavix triggers a completed event callback. The JSON payload includes a machine_detected boolean field that indicates whether the call was screened by the AMD system. Sample completed event payload: 
{
  "uuid": "5dccb6b0-f35c-488c-867b-86fb012c4415",
  "direction" : "outbound",
  "event_type": "completed",
  "event_time": "2025-09-22T12:56:45.000Z",
  "event_payload": null,
  "call_started": "2025-09-22T12:56:38.000Z",
  "call_answered": "2025-09-22T12:56:40.000Z",
  "call_completed": "2025-09-22T12:56:45.000Z",
  "from": "+18045961058",
  "to": "17653889567",
  "machine_detected": true,
  "tag": "marketing-campaign"
}
  • machine_detected: true: An answering machine or voicemail was detected.
  • machine_detected: false: A human was detected.
By listening for the completed event, your application can accurately log the outcome of the call, including whether it was dismissed by AMD or successfully answered by a human.