Voice agent architecture explained
A voice agent system is typically built from a few connected layers, a telephony layer that handles the actual phone connection, a speech processing layer that converts audio to text and back, and a language model layer that decides what to say.
The telephony layer
This layer handles placing or answering the actual phone call, using a provider that connects to the public phone network. It's responsible for call setup, audio streaming, and call teardown, independent of what's actually being said on the call.
The speech processing layer
Sitting on top of telephony, this layer converts the caller's audio into text in real time using speech to text, and converts the AI's generated response back into audio using text to speech, ideally with minimal added latency.
The reasoning layer
A language model, given context about the conversation so far and instructions specific to the use case, decides how to respond at each turn. This is the layer that actually determines what the agent says, versus just how it sounds.
The orchestration and event layer
Coordinating all of this in real time, streaming events like transcript updates and call status back to a dashboard, and triggering downstream actions like booking a meeting once the call ends, is typically handled by an orchestration layer sitting above the other three.
Frequently asked
Not always, many platforms combine specialized providers for telephony, speech processing, and language models rather than building every layer from scratch.
More in Technical
Voice AI architecture generally follows a pipeline, speech to text converts what's said into text, a language model decides on a response, and text to speech converts that response back into audio, all repeated for each turn of the conversation.
A voice agent API generally lets you send leads into a calling campaign programmatically, trigger and manage campaigns through code, and pull call data, transcripts, and outcomes back into your own systems on demand.
Voice agent webhooks send a real time notification to an endpoint you control whenever something happens, a call completes, a lead status changes, or a meeting gets booked, letting you build custom logic on top of that event instead of polling for updates.
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