voice-ai-development

Stream every stage of the pipeline: use interim STT results from Deepgram, stream LLM tokens, and start ElevenLabs TTS before the LLM finishes. Non-streaming pipelines add seconds of delay and break conversational flow.

Use the OpenAI Realtime API when you want integrated voice-to-voice without managing separate STT and TTS providers. Choose Deepgram plus ElevenLabs when you need best-in-class transcription accuracy and voice quality in a custom pipeline.

Implement barge-in detection using voice activity detection to notice when the user starts speaking. Stop TTS playback immediately and clear the audio queue so the agent feels responsive rather than robotic.

Yes, Vapi provides hosted voice agents that connect to phone numbers via Twilio and handle calls through webhooks. You configure the assistant's model, voice, and transcriber, then process function calls and end-of-call reports in your webhook endpoint.

Latency varies by provider and network conditions, per-minute costs accumulate quickly, and debugging distributed streaming pipelines is complex. Mixing providers avoids lock-in but increases integration effort.