Senior Software Engineer

What we do Idler builds reinforcement learning environments that teach AI models to code like 0.01% engineers. Our training environments are based on real-world coding scenarios that frontier models will actually encounter. We've closed a multimillion-dollar contract with a leading foundation lab (the largest they've issued to date). Demand is outpacing our capacity to deliver, so we're scaling the team fast. What you'll do Build agentic systems that create and QA coding environments at scale. Most of your day will be spent designing these systems to be extremely sound. A big part of our work is thinking critically about what makes a coding environment and task "good" and "fair". This requires high agency and philosophical thinking alongside technical execution. Concretely, you'll : Design and build scaleable systems that generate RL environments Create automated QA systems to validate environment quality and fairness Work directly with AI researchers at leading labs to understand what makes training data effective Support new product lines as we expand beyond coding environments You'll work with The founding team, a founding engineer, and a small group of engineers (we're hiring quickly). You'll have direct access to AI researchers at frontier labs. Tech stack Typescript, React, NodeJS, Postgres, Redis, Vercel, Cursor Benefits Healthcare coverage, 401(k), and 15 days PTO. Meals, coffee, and snacks (that you will actually enjoy) covered during working days. Latest MacBook Pro and equipment. Relocation assistance available. Team offsites and events (we love hanging out). This is an in-person role in San Francisco. We're a tight-knit founding team and we play to win. Join us if you like to win too.