Full-Stack Engineer, Agent Evaluation & Reliability

ABOUT THE ROLE Join an AI team building backend infrastructure for agent evaluation and continuous improvement. This backend-leaning full-stack role offers ownership of architecture and product decisions while turning complex systems into useful customer-facing features. WHAT YOU'LL DO - Build and maintain backend systems that power agent evaluation and continuous improvement. - Design data models for evaluation datasets, experiment runs, agent traces, knowledge versions, findings, and customer-defined quality criteria. - Develop and support enterprise integrations, including authentication, OAuth, webhooks, incremental syncs, backfills, rate limits, retries, and monitoring. - Own features end to end, from technical design and implementation through deployment, observability, customer feedback, and iteration. - Work directly with customers to diagnose system failures and turn individual needs into reusable product capabilities. - Debug distributed workflows and improve system reliability. WHAT WE'RE LOOKING FOR - Two to four years of experience in a full-stack or backend engineering role building and shipping production systems. - Production experience with TypeScript and Node.js or Bun, PostgreSQL schema design, and queues or worker systems. - Hands-on machine learning engineering experience, including model development, and familiarity with agent infrastructure, LLM evaluation, tracing, or agent memory systems. - Experience building backend systems and third-party integrations, and owning projects from design through deployment and iteration. - Understanding of how evaluating nondeterministic agent systems differs from conventional unit testing. - Experience in a fast-paced startup environment and a track record of building, such as through shipped AI projects or open-source contributions. COMPENSATION & BENEFITS Base salary is $120,000 to $180,000 USD annually. Visa sponsorship is available, including H-1B transfers, OPT, and O-1. LOCATION On-site in San Francisco, California, United States.