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When making outbound calls, your phone agent may encounter voicemails or IVR (Interactive Voice Response) systems. You can configure your agent to automatically detect these and take appropriate action.

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Voicemail detection

The system runs voicemail detection continuously within a timeout window. You can choose what happens when a voicemail is detected:
  • Hang up — disconnect immediately, even if the voicemail greeting is still playing.
  • Leave a message — wait for the agent’s turn to speak, then deliver a message. Supports dynamic variables.
If the timeout is reached without detecting a voicemail, detection stops and the call continues normally.
1

Enable voicemail detection

Navigate to your agent settings, then open Call Settings and enable Voicemail Detection.
2

Choose voicemail behavior

Select one of the following options:
  • Hang up if reaching voicemail: The agent disconnects when it detects a voicemail.
  • Leave a message if reaching voicemail: The agent waits for its turn to speak, then leaves a message. Choose between:
    • Prompt: A dynamically generated message based on instructions you provide, such as Summarize the call and ask the user to call back.
    • Static Sentence: A fixed message, such as Hey {{user_name}}, sorry we could not reach you directly. Please give us a callback if you can.

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IVR hangup

When enabled, the system detects if your outbound call reaches an IVR (automated phone menu) system and automatically hangs up the call.
IVR hangup is separate from IVR navigation, which allows your agent to interact with and navigate through IVR menus using DTMF tones.
To enable, navigate to your agent settings, then open Call Settings and toggle on IVR Hangup.

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FAQ

This most likely means the call is being classified as an IVR rather than a voicemail. Because the two detection types are handled separately, voicemail hang up will not trigger in this case. Enable IVR Hangup in your agent’s Call Settings to handle this scenario and automatically disconnect when an IVR system is detected.
No, voicemail and IVR detection will only run for the first 3 minutes of the call. Please contact support@retellai.com if you need to extend this.
Voicemail detection is optimized for real-time use cases and generally adds under 30ms of latency.
If voicemail is detected, the call will have a disconnection reason of voicemail_reached. If IVR is detected, the disconnection reason will be ivr_reached.
Yes. When set to hang up, the agent disconnects immediately upon detection, regardless of whether the voicemail greeting is still playing.
No. When set to leave a message, the agent waits for its turn to speak before delivering the message.