CTO – Technical Lead, AI Voice Agent, SIP Migration, Retell/Vapi

This is a fully remote position, open to applicants in Argentina.

📋 Description

• Oversee the complete technical architecture and implementation of an AI voice agent system that enhances the phone infrastructure of a live law firm.

• Plan and implement a phased migration from PBX to SIP, ensuring rollback controls are in place at each stage to keep the firm operational.

• Direct and coordinate a team of 2 OST engineers during the MVP stage of the project.

• Conduct weekly demonstrations and maintain accessible test endpoints for both OST leadership and the client to track progress firsthand.

• Define and manage non-functional requirements such as uptime, latency SLOs, observability, failover, and call quality monitoring.

• Decompose the overall implementation scope into distinct phases (Phase 1 / 2 / 3), each providing independent value, along with milestone-based payment checkpoints.

• Serve as the primary technical liaison with the client, simplifying complex infrastructure choices into clear and confident guidance for non-technical stakeholders.

⛳️ Requirements

• Proven hands-on experience with PBX-to-SIP migrations, having personally transitioned a live organization from a traditional POTS/PBX system to a modern SIP trunk (such as Twilio, Telnyx, Sierra, or similar); can articulate the nuances of the physical-to-software boundary.

• Experience in phased rollout design, having constructed parallel SIP and legacy environments with incremental traffic transitions (1% → 5% → 25% → 100%) and rollback capabilities at each stage.

• Background in production voice AI, having deployed real-time voice agent solutions utilizing Retell, Vapi, LiveKit, or comparable technologies; comprehends latency budgets, turn-taking, and interruption management.

• Knowledgeable about privacy and compliance issues, including PII, financial data, attorney-client privilege, Retell BAA coverage, and data retention requirements for regulated environments.

• Prioritizes non-functional requirements as essential deliverables, treating observability, uptime SLOs, failover, and call quality monitoring as critical components rather than afterthoughts.

• Excellent English communication skills, capable of reassuring non-technical stakeholders and conducting structured weekly demos for both the client and internal OST leadership.

🏝️ Benefits

• Competitive pay of $150 – $200/hour, compensated in USD via bank transfer for US-based candidates or through Deel for LATAM-based candidates.

• Fully remote position, requiring a strong understanding of the US market and phone systems.

• Freelance / Hourly contract format, with an expectation of higher hours during the early phases of the project, tapering as the build stabilizes.

• Referral program available, allowing you to earn a bonus for referring talent that gets hired.