Backchannel lets the agent make small acknowledgment sounds — like “uh-huh”, “I see”, or “okay” — while the caller is speaking. This improves engagement and makes the conversation feel more natural.Documentation Index
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Configuration Fields
Set these fields via the Create Agent API or your agent settings:enable_backchannel
Set to true to enable backchannel. Defaults to false.
backchannel_frequency
Controls how often backchannel triggers when the engine determines a backchannel is appropriate. Range: 0 (never) to 1 (always). Default: 0.8.
backchannel_words
The words the agent can use as backchannels. Defaults vary by language and voice provider. You can override this field to customize the words used.
Certain voices do not work well with certain words. Experiment before customizing the word list.
Default Backchannel Words by Provider
- English (en)
- Other languages
| Voice provider | Default words |
|---|---|
| ElevenLabs | "okay", "uh-huh", "mhmm", "yah" |
| OpenAI | "okay", "uh-huh", "yah" |
| Deepgram | "okay", "uh-huh", "yah" |