Software Engineer – Real-time Voice Agent Platform

About the role

Cartesia builds real‑time multimodal intelligence, delivering fast state‑of‑the‑art voice models and a platform for production‑grade voice agents. As a Software Engineer on the Agent Harness team you will own the end‑to‑end stack that powers Managed Agents, shaping latency, reliability and developer experience.

Key responsibilities

• Evolve the real‑time transport layer that carries audio between users and agents, expanding connectivity across web, SDKs and telephony without increasing latency or degrading quality.
• Trace and cut end‑to‑end conversational latency across the STT, LLM and TTS pipeline.
• Make agent deployments faster and more resilient with quicker cold starts, smarter scaling and graceful behavior under load.
• Define voice‑agent quality metrics, build evaluation suites and regression tracking to catch quality and latency regressions before release.

Required profile

• Proven experience building and operating distributed backend systems in production, preferably at a high‑growth startup.
• Strong product instincts focused on customer‑facing latency, reliability and developer experience.
• Fluent use of coding agents and habit of staying at the frontier of technology.
• Clear communication with technical and non‑technical audiences and strong presence in design reviews.

Required skills

• Real‑time media systems such as WebRTC, SIP or RTP.
• Voice‑agent frameworks like Pipecat, LiveKit, OpenAI Agents SDK, Claude SDK or Vercel AI SDK.
• Developer‑facing platforms or infrastructure, e.g., SDK back‑ends or API platforms.
• Distributed systems at scale, including autoscaling, multi‑region architectures and queue‑based designs.

What we offer

• Competitive base salary with an attractive equity package.
• Fully covered medical, dental and vision insurance for you and your family.
• Parental leave – 9 weeks paternity and 12 weeks maternity.
• 401(k) retirement plan.
• Monthly commuter allowance.
• Flexible PTO – take time off as needed.
• Daily meals and snacks provided.
• Equal‑opportunity inclusive culture.