Founding Engineer

existing customers, a dedicated GTM team, and the infrastructure to move fast. You’ll be joining at day zero, but with a real runway. In terms of what we’re building, the tech matters less than you’d think. We care about your ability to move fast, make good decisions with incomplete information, and build things people actually want to use. That said, strong Ruby on Rails experience on the backend and solid React or TypeScript on the frontend will go a long way. If you’ve ever wanted to work in a small, scrappy team with the energy of an early-stage startup but without the typical early-stage uncertainty, this is that opportunity. Ready to be part of the challenge? About the team Our Engineering team is the engine behind Factorial, crafting the tech that makes HR simple, fast, and reliable for thousands of companies. If you love solving hard problems and want to build something that truly matters, come build it with us. We’re a team of 200 Product Engineers building Business Management solution that actually works for the people using it. Our core stack is Ruby on Rails and React but the interesting work right now is what we’re building on top of that: agentic workflows, LLM-integrated features, systems that behave probabilistically rather than deterministically. You’ll join the newly formed IT Management domain, where we’re creating a platform to manage onboarding, permissions, support, and equipment, so new employees are productive from day one. If you’re excited about shaping a new product area, owning features end-to-end, and working in a people-first company with a strong engineering culture, this role is for you. Our mission in the IT Management Domain is building this new product in Factorial, including multiples moving pieces (inventory management, support ticketing, MDM, IdP, integrated onboarding, etc.), so employees are productive as soon as they receive the equipment and complete the onboarding process. What are we looking for? - You have an entrepreneurial mindset and genuinely enjoy the early stage of building something from scratch. - You’ve shipped AI-powered features and know that evaluating them in production is the hard part, not building them. You think about reliability and user friction before model complexity. - You’re comfortable reviewing agentic workflows and have opinions about LLM architecture tradeoffs. Not just theoretical ones. - You treat AI features as hypotheses. Build, deploy, measure, adjust. You own that whole loop, not just the build part. - You can break down non-deterministic outputs into something the rest of the team can reason about and act on. - You’re comfortable working with Ruby on Rails & React and understand how to integrate AI models into scalable, cloud-native environments. - You help teammates who are transitioning from deterministic to probabilistic thinking, not by lecturing, but by working through it together. - 4 years in software engineering, with some track record (or serious curiosity) around shipping AI features. - You can explain a complex technical decision in English to someone who doesn’t write code clearly, without condescension. What You’ll be Doing? - You will be a Founding Engineer, taking ownership of big initiatives, and being interested in the outcome, not just the output.