Build AI Call Agents with OpenAI Realtime SIP: The Manual Way vs. RealtimeSIP

TL;DR: OpenAI's Realtime SIP API lets you connect phone calls directly to GPT-4o for natural voice conversations. You can build it yourself with Twilio + Node.js (8+ hours, 300+ lines of code) or use RealtimeSIP (paste API key, 5 minutes, zero code)....