Senior Full-Stack Engineer — Platform

Lumos; San Francisco (CA); On-site; USD 140,000 - 210,000; Full time

Benefits offered by this job

Annual performance bonus

Stock options

Job summary

Lumos in San Francisco is seeking a senior full-stack engineer to own backend services and the Next.js/React frontend that power our data and RL platforms, including the data lab network of experts producing gold-standard data.

We are an AI-native team that automates aggressively using coding agents. You will lead end-to-end system ownership, collaborate with product, research, and data teams, and help shape our engineering culture in a fast-paced environment.

Qualifications

• Senior full-stack engineering experience (typically 5+ years).
• Python as a primary language with solid frontend capability (Next.js/React).
• Proven track record owning systems end to end — from design through production operation.
• Expert-level, hands-on experience with agentic AI and AI-assisted development.
• Enthusiasm for pioneering new AI tools and workflows in an AI-native team.
• Hands-on experience with Google Cloud Platform (compute, storage, networking).
• Experience integrating third-party APIs and AI/LLM vendor services into production systems.
• Comfort with modern engineering practices: version control, CI/CD, testing, observability.
• Fluent English, written and spoken.

Responsibilities

• Design, build, and operate backend services and APIs powering data and RL platforms.
• Contribute across the stack, including frontend work in Next.js/React.
• Integrate and orchestrate AI capabilities across model providers; optimize cost and latency.
• Build and maintain infrastructure on Google Cloud.
• Promote AI-native engineering practices and tool use.
• Evaluate and roll out new agentic tools and workflows to the team.
• Write clean, well-tested code and mentor teammates.
• Collaborate with product, research, and data teams to ship features.

Skills

Python

Frontend development

System ownership

AI tooling

Code review/mentorship

Tools

Next.js

React

Google Cloud

CI/CD

Job description

Lumos is a health and life-science AI research lab focused one evlas and training. Our mission is to make health and life-science AI genuinely accurate and safe. We build the benchmarks, RL environments, and adversarial testing frameworks that the industry rely on to know whether their models can be trusted with science.

We're scaling our SF team to support new product launches and foundational lab partnerships — startup velocity, frontier-model stakes, and pure research work.

The Role

You'll own backend services and APIs — and the full stack around them — that power our data and RL platforms, including Labela where our network of domain experts produces gold-standard data.

We're an AI-native team. We automate aggressively and use AI agents to write, review, and maintain our code and infrastructure — and this is the role where that matters most. We're looking for a leading practitioner of agentic software development who treats coding agents as a core part of the toolchain, pioneers new agentic tools and workflows, and rolls out what works to the rest of the team.

What You Will Do

• Design, build, and operate backend services and APIs that power our data and RL platforms.
• Contribute across the stack, including frontend work in Next.js / React.
• Integrate and orchestrate AI capabilities across multiple model providers (OpenAI, Anthropic, Google, and others) — prompt orchestration, evaluation, and cost / latency optimization.
• Build and maintain infrastructure and services on Google Cloud.
• Drive our AI-native engineering culture — using and orchestrating coding agents to build, test, refactor, and maintain systems, and continuously improving how we do it.
• Pioneer and evaluate new agentic tools, frameworks, and workflows, then roll out what works to the rest of the team.
• Write clean, well-tested, maintainable code, and set engineering standards through review and mentorship.
• Collaborate closely with product, research, and data teams to turn ideas into shipped features.

What You Bring

• Senior full-stack engineering experience (typically 5+ years), with Python as a primary language and solid frontend capability (Next.js / React).
• A proven track record owning systems end to end — from design through production operation.
• Expert-level, hands-on experience with agentic AI and AI-assisted development — using coding agents and AI tooling in real production work, and a strong point of view on how to do it well.
• Genuine enthusiasm for pioneering new AI tools and workflows, and for raising the bar for how an AI-native team operates.
• Hands-on experience with Google Cloud Platform (compute, storage, networking, deployment).
• Experience integrating third-party APIs and AI / LLM vendor services into production systems.
• Comfort with modern engineering practices: version control, CI/CD, testing, observability.
• Fluent English, written and spoken — our primary working language.

Nice to Have

• Experience building or working with reinforcement-learning systems.
• Experience scraping and ingesting data from diverse external sources.
• Interest in or exposure to health / life-science domains.

Compensation

• Annual performance bonus
• 20,000–50,000 stock options

Work Authorization

Candidates must be authorized to work in the US without sponsorship. Lumos does not sponsor work authorization for this role.

Lumos is an equal opportunity employer. We are committed to building a diverse and inclusive team and do not discriminate on the basis of race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, or any other characteristic protected by applicable law. All qualified applicants will receive consideration for employment.