Build a Production Voice Agent This Weekend: Realtime API + MCP + SIP (Step-by-Step)
Last Updated on September 14, 2025 by Editorial Team
Author(s): Tarun Singh
Originally published on Towards AI.
AI That Picks Up the Phone: Realtime Voice Agents with SIP, MCP, and WebRTC
TL;DR: In this hands-on guide you’ll ship a fully working Realtime API voice agent with WebRTC speech-in/speech-out, server-executed MCP-style tools, and SIP calling AI stubs for Twilio/CPaaS. We’ll keep latency low, add DTMF fallbacks, and prep you for a real AI contact center rollout.
This article provides a comprehensive guide to building a production-ready voice agent using the Realtime API, SIP, and WebRTC. It covers features such as low-latency voice processing, DTMF fallbacks, and integration with tools like Twilio. The guide emphasizes a hands-on approach, encouraging developers to clone the provided repository, set up their environment, and configure necessary components to run the voice agent effectively. Additionally, the article offers insights into design patterns, architecture considerations, and practical tips for ensuring robust performance and compliance in real-world applications.
Read the full blog for free on Medium.
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