Senior Backend Engineer — RL Environments on Google Cloud

Lumos; San Francisco (CA); On-site; USD 162,000 - 198,000; Full time

Job summary

Lumos is a health and life-science AI evaluation company based in San Francisco. We are expanding our backend engineering team to build and operate scalable RL environments on Google Cloud using Python, turning research ideas into reliable production systems.

The role focuses on designing, implementing, and maintaining the infrastructure that runs rewards, verifiers, and evaluation logic, collaborating closely with research, data, and product teams.

Qualifications

• Senior backend engineer with 5+ years of experience
• Strong Python expertise
• Hands-on with Google Cloud Platform
• Experience integrating third-party APIs into production systems
• Familiar with modern engineering practices: CI/CD, testing, observability

Responsibilities

• Build and operate RL environments and harnesses at scale
• Implement verifier and grader plumbing based on research designs
• Maintain infrastructure on Google Cloud: compute, storage, networking, deployment
• Integrate model providers (OpenAI, Anthropic, Google, others) with attention to cost and latency
• Write clean, well-tested code and set standards through code reviews
• Collaborate with research, data, and product teams to ship running systems

Skills

Python

Backend engineering

Google Cloud Platform

CI/CD

Testing

Observability

Version control

API integration

Go

Job description

Lumos is a health and life-science AI evaluation company based in San Francisco. We are expanding our backend engineering team to build and operate scalable RL environments on Google Cloud using Python, turning research ideas into reliable production systems.

The role focuses on designing, implementing, and maintaining the infrastructure that runs rewards, verifiers, and evaluation logic, collaborating closely with research, data, and product teams.