A voice agent feels like one smart caller, but it is a pipeline of small parts that must respond in well under a second.
The pipeline
- Telephony: Twilio connects the phone call and streams the audio.
- Speech-to-text: converts what the caller says into text as they speak.
- LLM: decides the reply using the conversation so far and your business rules.
- Text-to-speech: turns the reply into natural audio.
- CRM: stores the outcome, such as lead status, objections and the next follow-up.
Frameworks such as Pipecat orchestrate these steps in real time.
What makes it feel natural
- Low latency: stream every stage instead of waiting for full results.
- Interruptions: stop talking when the caller starts (barge-in).
- Memory: keep context so the agent never asks the same question twice.
What to get right in production
Add guardrails, a hand-off to a human, retries for missed calls and a transcript for every call. Measure call outcomes, not just how the voice sounds.