AI Voice Agent Development

Most voice agents run a pipeline of three stages. Speech-to-text streams the caller audio into a live transcript; a language model reads that transcript together with the call context, decides what to say and which tools to call, such as checking a calendar or looking up an order; and text-to-speech turns the reply back into audio. A newer alternative is a speech-to-speech model that handles audio in and out directly, which can sound more natural but gives less fine-grained control over each stage.

Choosing between them is a trade-off between naturalness, control, cost per minute and how easily you can inspect and test what the agent heard and said. We pick components per use case - a strong transcription model matters most for names, addresses and account numbers, while a booking line may care more about voice quality and speed - and keep the components swappable so you are not locked to one vendor.

On the phone, delay is what makes an agent feel robotic. People expect a reply within roughly a second of finishing a sentence, so every stage has to stream: transcription produces partial text while the caller is still speaking, the model starts generating as soon as the turn ends, and speech synthesis begins playing the first words before the full reply is written. Slow tool calls are covered with short natural acknowledgements rather than silence.

Turn-taking is the harder problem. The agent has to tell a finished sentence from a thinking pause, and it must stop talking immediately when the caller interrupts - known as barge-in - without being triggered by background noise, a cough or the caller saying mm-hmm. We tune end-of-turn detection and interruption handling on recordings of real calls from your line, because the right settings for a quiet office differ from those for callers on the road.

A voice agent connects to the phone network through a telephony provider or SIP trunk, which lets it answer your existing numbers or place outbound calls without changing what customers dial. It can sit in front of your current phone system or contact-centre platform as the first point of contact, or take overflow and after-hours calls only, while your routing rules stay in place.

Transfers need as much design as the conversation itself. A warm transfer passes a summary, the caller details and the reason for escalation to the human agent so the caller never repeats themselves; a cold transfer simply routes the call. We define clear triggers - caller requests, repeated misunderstanding, sensitive topics, payment steps - and fallbacks for when no one is available, such as a callback request or a voicemail that lands in your CRM.

Rules on recording calls and on automated or AI-generated voices vary by country and region. Some jurisdictions require every party to consent to recording, many expect callers to be told they are speaking with an automated system, and outbound calling with artificial voices is often subject to stricter consent and do-not-call rules. Your legal team should confirm the requirements for each market; we build the agent so disclosures, opt-outs and consent capture are configurable per line and per region.

On the data side, transcripts and recordings can contain personal and sometimes payment or health information. We support redacting sensitive fields from transcripts, pausing recording during card capture or routing payments to a compliant payment flow, setting retention periods, and keeping data within the regions and providers you approve.