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Overview

Flow Builder supports voice deployment through Telnyx. Connect a phone number to your flow so inbound callers interact with your AI agent over a live phone call with real-time speech processing.

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How It Works

  1. Telnyx receives the inbound call and forwards it to your flow’s voice endpoint
  2. Flow Builder processes each turn: speech-to-text → node execution → LLM call → response
  3. Responses stream back via SSE for low-latency text-to-speech playback
  4. Conversation continues until an End node is reached or the caller hangs up

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Setup

1

Create a Telnyx Account

Sign up at telnyx.com and purchase a phone number.
2

Configure the Webhook

In Telnyx, set the phone number’s webhook URL to your flow’s voice endpoint (found in Flow Builder’s deploy settings). Set the method to POST.
3

Save and Test

Save the Telnyx configuration. Call your number to test the flow.

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Voice-Specific Best Practices

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Troubleshooting

Test your flow thoroughly using the built-in test panel before connecting to a live phone number.

Engine & Streaming

How streaming works for voice

Testing

Test before deploying

Embedding Widget

Deploy to chat instead

API Key Setup

Required for voice