Healthcare clinics, home-services companies, logistics brokerages, and financial call centers automating inbound and outbound telephone calls frequently search to hire a freelance AI phone agent (Twilio Media Streams, LiveKit SIP, OpenAI Realtime, Vapi, Retell) programmer. I am Aldian Fazrihady, a Senior Freelance AI Application Engineer available via Upwork.
Core Telephony & Conversational Voice AI Capabilities
- Bi-Directional Twilio WebSockets & SIP Trunking: Streaming raw `mulaw` 8kHz / PCM audio frames over WebSockets or LiveKit SIP trunks with sub-500ms voice-to-voice turnaround and natural barge-in interruption handling.
- Real-Time Function Calling Mid-Call: Checking live calendar availability, booking appointments into EHR/CRM systems, verifying caller identity via OTP, and executing warm SIP transfers to human agents.
- Post-Call Diarization, QA & Sentiment Scoring: Storing dual-channel call recordings in S3 and extracting structured QA scorecards into PostgreSQL.
Frequently Asked Questions
Can we build our own custom Twilio + Deepgram + LLM + ElevenLabs pipeline instead of paying per-minute wrapper markups?
Yes! Building a direct streaming WebSocket/SIP pipeline on your own cloud cuts per-minute telephony AI costs by 50–70% while giving you 100% control over latency and HIPAA/SOC 2 data residency.
How can we hire you as a freelance AI phone agent programmer?
Contact me on Upwork.