Job Details

Role: Founding Full-Stack Engineer
Employment Type: Full-time, On-site
Location: San Francisco, CA
Compensation: $170k - $230k base + competitive equity
Visa: Not available
Company Overview

Kaizen builds reinforcement learning environments that allow AI to train from its own experience instead of relying on human-labeled data - solving the core infrastructure bottleneck to achieving autonomous agentic AI systems.
In just 5 months, they've secured massive contracts with frontier AI labs, have a 3-person founding team, and are scaling rapidly with strong funding and runway.
Role Summary

As employee #4, you will own features end-to-end across the stack - from database to UI - and build production systems that support high-volume autonomous AI training workloads for the world's top AI research labs.
Key Responsibilities

• Architect full-stack applications with React.js (frontend) and Python (backend)
• Deploy scalable infrastructure on AWS/GCP for AI training systems
• Transform cutting-edge AI research into production-ready tools
• Lead technical decisions in a microservices architecture
• Help define engineering culture as the team grows from 3 → 30+ engineers

• 2-5 years building large-scale production applications
• Expert React.js skills (complex frontend leadership experience)
• Backend mastery with Python (FastAPI, Django, or Flask)
• Full-stack versatility - strong frontend + backend skills
• Experience deploying real production systems on AWS/GCP
• Broad domain exposure (marketplaces, real-time portals, varied use-cases)
• Bonus: DevOps/CI-CD, Redux/Zustand, Docker, public portfolio, microservices

• In-person in San Francisco (high-collaboration environment)
• Elite engineering team solving the hardest problems in AI
• Mission-driven, high-ownership role with direct product impact
• Ground floor of a high-growth AI infrastructure startup