Fullstack Software Engineer (AI Infrastructure)

Full-time | On-site | San Francisco, CAThe Mission We aren't just another AI company; we are the engine behind the industry's giants. We partner directly with all 5 of the world's leading AI labs to push the frontiers of LLMs and AI Agents. If you want to work on the most complex infrastructure powering the next generation of agentic and hard-reasoning workflows, this is the place.The Bar Following a $30M Series A, we are scaling a high-density team of 20. Our founding team comes from the most rigorous engineering environments at Google, Meta, and Bloomberg. We are looking for S-tier technical horsepower. This role is for engineers who have proven they can ship at the highest level of quality and velocity. We value extreme ownership, the ability to navigate deep technical ambiguity, and a "young and hungry" mindset that prioritizes building massive things over corporate process. You will be working alongside peers who have already conquered hard technical challenges and are now channeling that intensity into the future of AI.The RoleThis is a high-autonomy, high-impact position. You will have end-to-end ownership over projects that define how AI is evaluated and improved.Full-Spectrum Engineering: One week you’re prototyping a new RL environment from a research paper; the next, you’re deploying distributed experiments on Kubernetes or building Kafka pipelines for real-time analytics.Ship Relentlessly: Collaborate with research and product teams to move from concept to production at breakneck speed.Build for Scale: Contribute to the core infrastructure that leading AI labs and YC's top companies rely on for data creation and experimentation.What We’re Looking ForExperience: 1–3 years as a Fullstack SWE with a track record of shipping high-quality code.The Stack: Mastery of TypeScript/JavaScript (Next.js, React, Node.js) and Python.Systems: Experience with (or hunger to master) Kubernetes, Kafka, Redis, and Elasticsearch.Mindset: You are "young and hungry," eager to build something massive, and thrive in a talent-dense, tight-knit environment.Compensation & UpsideWe offer a compensation package designed for high performers:Base Salary: $180K - $220K (Flexible for elite backgrounds) + Sign-on bonus.Total OTE: $410K - $450K.Uncapped Bonus: $230K target + 4% of profits from your vertical’s contracts (Avg. contract $8M at 70% margin).Equity: Competitive founding-level equity.Office CultureWe operate with the intensity of a trading floor and the innovation of a research lab.Location: 5 days a week in our San Francisco office (with Sundays being remote or half-day).Environment: Fast iteration, open communication, and a team that has become close friends while moving at light speed.The ProcessInitial Screen (30m) ➔ Technical Round ➔ Take-Home (6h) ➔ 2-Day SF Work Trial ➔ Offer.Join the team building the foundation for the world's top AI models.