The Open-Source Voice AI Stack Every Developer Should Know in 2026

"Voice AI just had its "ChatGPT moment." A year ago, building a voice agent meant stitching together five different APIs and paying multiple vendors per minute of conversation. Today the open-source ecosystem has genuinely caught up - and it's moving fast. I've been deep in this rabbit hole building Dograh, an open-source voice agent platform like n8n. This post is basically the research I wish existed when I started. Here's the full OSS stack - from raw audio all the way to a deployed phone agent. The Stack at a Glance A production voice agent has five layers: Telephony / Transport -> Twilio, Vonage, WebRTC STT (Speech-to-Text) -> Parakeet, Canary Qwen, Silero VAD LLM -> GPT-4o, Claude, Llama 3 TTS (Text-to-Speech) -> Chatterbox, Kokoro, XTTS-v2 Orchestration -> Dograh, Pipecat, LiveKit Agents Every single layer now has solid open-source options. Let's go through them one by one. Speech-to-Text If you're building anything real-time, you need something built for streaming from the grou