Research Engineer

San Francisco, CA | Onsite | Competitive Salary + Meaningful EquityWe're partnering with a well-funded, early-stage AI start-up tackling one of the biggest challenges in the future of computing. Their mission is to build intelligent systems capable of solving highly complex engineering problems autonomously, combining cutting-edge AI research with real-world product development.This is a rare opportunity to join a small, elite team working at the intersection of frontier language models, reinforcement learning, AI agents, and large-scale software systems.What You'll Be DoingResearch and build next-generation AI agents capable of solving complex technical problems.Develop and improve post-training strategies for frontier language models.Design, implement and evaluate RL environments for agent learning.Build novel agent workflows, benchmarks and evaluation frameworks.Prototype quickly while writing production-quality software that ships to customers.Work closely with world-class engineers and researchers to turn cutting-edge ideas into real products.What We're Looking ForStrong software engineering fundamentals.Hands-on experience building and working with reinforcement learning environments.Evidence of meaningful AI research projects alongside strong implementation experience.Comfortable using modern AI development tools such as Cursor, Claude Code or similar AI-assisted engineering workflows.Passion for solving difficult technical problems in a fast-moving start-up environment.