Enterprise sales organizations face the challenge of delivering consistent, high-quality coaching to every field representative regardless of geography or manager availability. An AI-powered voice coach accessible on demand through natural conversation offers an alternative, but building real-time voice AI introduces infrastructure complexity related to bidirectional audio streaming, WebSocket management, and scaling. This post introduces a fully serverless pattern using AWS AppSync Events, Amazon Nova Sonic, and Amazon Bedrock AgentCore, implemented in a production deployment of an AI sales coach for a large enterprise beverage CPG company. Field representatives use voice conversations to prepare for account visits with personalized product recommendations, cross-sell strategies, and objection handling. The result is enterprise-grade sales coaching at approximately $0.007 per five-minute session, with zero idle infrastructure costs. The pattern is reusable in any application needing real-time bidirectional communication between a web client and a backend container. The architecture uses AWS AppSync Events as a serverless real-time audio transport layer between the rep’s browser and an Amazon Nova Sonic voice agent running on Amazon Bedrock AgentCore. AppSync Events is a serverless WebSocket API enabling real-time pub/sub messaging, handling connection management, message routing, fan-out, and auto scaling without server infrastructure. The pattern uses two dedicated channels per session: an upstream channel where the web client captures microphone audio, encodes it as base64 PCM chunks, and publishes each chunk, and a downstream channel for processing.