Founding Software Engineer

San Francisco, CA On-site Full-time Compensation: $150,000–$200,000 + 0.5%–2% equity About The Company Our client is an early, seed-stage startup building data infrastructure and reinforcement learning environments that leading AI labs use to train and evaluate their models. Their platform lets AI teams spin up custom evaluation datasets and annotation pipelines from plain-English descriptions, automating interface generation, instructions, QA, and annotator management. They're well-backed by top-tier investors and led by a founding team out of leading AI and technology companies. Founded 2025 1–10 people Industry: AI Tools The Role A founding engineering role on a lean team, reporting directly to the CEO. You'd own large technical pipelines end-to-end, translating ambiguous requirements into shipped systems while balancing speed and reliability as the company scales. What You'll Be Doing Own large scopes of technical pipelines from research through executionBuild and scale production-grade backend and full-stack systemsHelp set technical direction alongside the CEOMake system-design and scalability decisions as the product growsPick up new languages and tools as the work requires Requirements Solid computer science fundamentals and strong engineering craftHands-on experience shipping production-grade backend or full-stack systemsStrong system-design instincts and a real grasp of scalability tradeoffsComfort owning ambiguous problems end-to-end — research, tradeoff analysis, and delivery — without heavy hand-holdingA clear communicator with a strong ownership mentality Nice to Haves Time spent at startups or fast-scaling companiesExposure to applied AI or AI research, ideally in post-trainingBackground at a reinforcement-learning-environment company or applied AI lab Why Join A founding engineer seat with genuine end-to-end ownership and a direct line to the CEOWork that plugs straight into how modern AI models are trained and evaluatedEarly-stage momentum with strong backing and room to shape the technical direction Details Location — San Francisco, CAWork policy — On-siteCompensation — $150,000–$200,000 + equityVisa sponsorship — Available (O-1, OPT)Employment type — Full-time