---
title: "One-Second Voice-to-Voice Latency with Modal, Pipecat, and Open Models"
url: https://daily.dev/posts/one-second-voice-to-voice-latency-with-modal-pipecat-and-open-models-aejtkcqop
source_url: https://modal.com/blog/low-latency-voice-bot
type: article
source: "Modal"
published: 2025-11-04T22:13:07.962Z
updated: 2026-03-30T02:12:48.400Z
tags: ["python", "real-time-systems", "voice-ai", "webrtc"]
reading_time: 14
upvotes: 0
comments: 0
language: en
---

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# One-Second Voice-to-Voice Latency with Modal, Pipecat, and Open Models

**[Modal](https://daily.dev/sources/modal_labs)** · 14 min read · 0 upvotes · 0 comments

## Summary

Building a conversational voice AI bot with sub-second response latency using Modal's serverless platform, the Pipecat framework, and open-source models. The implementation achieves ~1 second voice-to-voice latency by combining Parakeet STT, Qwen3 LLM with vLLM, and Kokoro TTS. Key optimizations include using Modal Tunnels to bypass the input plane, WebRTC for client connections, regional pinning to minimize network latency, and independent autoscaling of GPU services. The demo includes a RAG-powered assistant for Modal's documentation with structured outputs and animated avatars.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://modal.com/blog/low-latency-voice-bot>

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---

Tags: [#python](https://daily.dev/tags/python), [#real-time-systems](https://daily.dev/tags/real-time-systems), [#voice-ai](https://daily.dev/tags/voice-ai), [#webrtc](https://daily.dev/tags/webrtc)

[View this post on daily.dev](https://daily.dev/posts/one-second-voice-to-voice-latency-with-modal-pipecat-and-open-models-aejtkcqop)