Cartesia
Software Engineer, Agent Harness
$180K–$250K
*HQ - San Francisco, CA · On-site · Full-time · Posted May 15, 2026
- Experience
- No strict years specified; the posting prioritizes shipped work.
- Visa sponsorship
- Visa sponsorship support is available and assessed case by case; success is not guaranteed and depends on factors including the role and work location.
About the job
Build and operate the platform behind Cartesia’s Managed Agents, improving real-time voice-agent transport, latency, reliability, deployment, and quality evaluation.
What you'll do
- Evolve real-time audio transport across web, SDKs, and telephony while maintaining latency and quality.
- Reduce end-to-end conversational latency across the STT, LLM, and TTS pipeline, and improve deployment speed and resilience.
- Build voice-agent evaluation suites, LLM-as-judge scoring, and regression tracking.
What they ask for
- Experience building and operating distributed backend systems in production.
- Strong product instincts focused on customer-facing latency, reliability, and developer experience.
- Fluent use of coding agents.
- Clear communication, sharp specifications, and effective participation in design reviews.
Nice to have
- Production experience with real-time media systems such as WebRTC, SIP, RTP, or low-latency audio.
- Experience with voice agents or agent frameworks, developer-facing platforms, or distributed systems at scale.
Pay
$180K – $250K (base salary)
Tools
WebRTC, SIP, RTP, Pipecat, LiveKit, OpenAI Agents SDK, Claude SDK, Vercel AI SDK
AI focus
Build and evaluate real-time voice agents, including quality measurement with LLM-as-judge scoring.
Model-written summary · the original posting is authoritative