Connect your first AI voice agent

Connect the telephone side of your AI voice application to Bird over SIP. Your conversational runtime handles speech, reasoning and tools; Bird connects the call.

Choose your setup path: Retell AI, Vapi or ElevenLabs. These guides map the provider’s actual SIP settings to Bird. For a PBX, use SIP client setup; to test telephony first, use a browser call or terminal call.

Use a runtime that supports SIP and obtain its incoming-call gateway settings. Prepare a simple conversation that answers a question before adding business-changing tools. Have a phone available for a controlled test.

Open Voice > SIP Trunks and create a named trunk. New trunks have both calling directions disabled.

For incoming calls, select Enable inbound and add the runtime's delivery gateway. Use the transport and destination settings supported by your runtime. Follow SIP trunks for the full connection configuration.

Open an eligible Voice number and route it to the trunk using receiving calls. Call that number from your test handset. Check that the runtime answers, receives caller audio and returns intelligible audio.

Find the same attempt in the call log. If no call reaches the runtime, check number routing and the delivery gateway before changing the agent prompt.

Select Enable outbound on the trunk. Configure the runtime with the trunk's SIP domain, supported transport and authentication method. For API-key authentication, the username is bird; use a key with Voice write permission and add it to the trunk's allowed keys.

Prepare an eligible caller identity, enable the destination and review placing calls. Call a handset you control and inspect both audio directions. An inbound test alone does not validate outbound settings.

Give the agent a read-only tool first, such as checking appointment availability. Then test an action that requires the caller's confirmation. The agent should confirm a booking only after the booking system confirms it.

Test an interrupted answer, a slow tool and an ambiguous request. Keep the call reference connected to the business record so support can distinguish telephone success from task completion.

Transfer to the intended receiving route and confirm that a person or queue receives the caller. Test the unavailable-route case too, with a useful callback or alternative response. See AI voice conversations for application behavior and voice troubleshooting for the telephone path.