Voice Agents Overview

Voice Agents turn your sender’s AI agent into a phone agent. It answers inbound calls to your number and places outbound calls, holding a real conversation over the phone — not a recorded message. The same agent you already use for SMS and WhatsApp powers the call: its provider, model, system prompt, tools, and knowledge bases all carry over. You enable voice on the agent, and Zavu handles the call.

​

How It Works

Each call runs through Zavu’s managed voice pipeline:

1. Speech recognition transcribes the caller in real time.
2. Your agent processes the transcript with its configured model, tools, and knowledge bases — exactly as it does for text channels.
3. Speech synthesis speaks the agent’s reply back to the caller.

The pipeline supports barge-in: the caller can interrupt while the agent is speaking, and the agent stops to listen. The agent can also call your tools mid-conversation, transfer the call to a human, or end it. You never manage telephony, audio streaming, or transcription. You configure the agent and call the API.

​

Inbound and Outbound

Both directions use the same agent configuration and produce the same call record and transcript.

​

Pricing

Voice calls are billed per minute of connected time plus telephony, deducted from your prepaid balance. A short-duration estimate is reserved when a call is placed, and you are charged for the actual duration when it ends. A hard duration limit (maxCallDurationMinutes, default 15) caps every call.

​

Calls and Transcripts

Every call is recorded as a call resource with its status, duration, cost, and a turn-by-turn transcript. Retrieve a single call to read its full transcript, or list calls to review recent activity. Subscribe to the call.* webhook events to react to calls in real time — for example, to log completed conversations or trigger follow-ups. See Webhooks.

​

Next Steps