Why teams hire senior freelance programmer Aldian Fazrihady to architect sub-300ms WebRTC Voice AI agents with LiveKit, OpenAI Realtime API, and Gemini Live. Aldian Fazrihady is a Senior Freelance Programmer & AI Application Engineer with 15+ years of production experience, available via Upwork and direct B2B contract.

1. Production Architecture: Low-Latency WebRTC Voice AI Pipelines with Barge-In & Deterministic Function Calling

import asyncio
from dataclasses import dataclass

@dataclass
class VoiceTurnState:
    session_id: str
    is_agent_speaking: bool = False
    current_audio_task: asyncio.Task | None = None

async def handle_user_vad_speech_start(state: VoiceTurnState) -> None:
    """Immediately interrupt TTS playback on user barge-in (<40ms latency)."""
    if state.is_agent_speaking and state.current_audio_task:
        state.current_audio_task.cancel()
        state.is_agent_speaking = False

2. Core Architectural Advantages

• Sub-300ms Mouth-to-Ear Latency: Streaming PCM16 audio frames over WebRTC data/media tracks rather than buffered HTTP REST requests.
• Instant Barge-In Handling: Voice Activity Detection (VAD) immediately cancels active TTS buffers when the caller interrupts.
• Audited Tool Execution: Executing CRM lookups, appointment scheduling, and Stripe payments mid-call with deterministic confirmation.

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4. Frequently Asked Questions (FAQ)