> Markdown version of [/jobs/ext/2724316-founding-engineer](https://www.wearedevelopers.com/jobs/ext/2724316-founding-engineer). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Founding Engineer - **Company:** Factorial - **Location:** Barcelona, Spain (Remote available) - **Salary:** €60,500.0 - €85,800.0 - **Contract:** Permanent contract - **Skills:** Artificial Intelligence, Cloud Computing, Code Review, Software Engineering, ReactJS, Large Language Models - **Published:** September 5, 2026 - **Apply:** https://www.adzuna.es/contact-us.html ## About the Role + 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. ## Description + You will be a Founding Engineer, taking ownership of big initiatives, and being interested in the outcome, not just the output. About the outcome, you'll also work with your team members to establish goals and plan a quarterly roadmap, putting special attention to the technical needs of our domain. + You will be involved in customer calls to learn about their pains & needs. + You will review code daily and get feedback on your own code at every pull request, from all team members, including juniors. + You will learn from the entire team, both on technical topics (performance, architecture…) and core skills, in an environment driven by engineering quality. You will also mentor junior team members and help them learn from your experience. How We Work (Barcelona Office) At Factorial, we believe the best products are built when people come together, in person to collaborate, challenge ideas, and move fast. That's why our Engineering Teams follows an office-first, flexible schedule. We work on-site several days a week, using that time to connect, align, and innovate as a team. However, we also understand the importance of focus and flexibility, so we support remote work when it makes sense - whether for deep work, personal needs, or just a change of scenery. This balance helps us stay agile, creative, and closely connected, while giving everyone the space to do their best work. At Factorial we don't evaluate you by years of experience but by your knowledge and skills. We use our Career Path with a rubric framework where we define what is expected for each experience level and skill. This framework allows you to know your current level and what you need to keep growing. We love transparency, so our Career Path includes the salaries for each level, which we share during the first interview to ensure alignment. Our Hiring Process 1. Intro Call * Chat with our Talent Partner about your journey and goals. 2. Hiring Manager Interview * Deep dive into your product mindset, teamwork, and problem-solving. 3. Live Challenge * A collaborative technical exercise based on real-life problems. 4. Final Coffee Chat * A relaxed conversation with our CTO & VP of Engineering to explore our vision, culture, and your growth. The whole process is remote, using videoconferencing tools! ## Related Videos - [You are not an AI developer](https://www.wearedevelopers.com/videos/1148-you-are-not-an-ai-developer) - [Green Cloud Computing](https://www.wearedevelopers.com/videos/592-green-cloud-computing) - [Watch Tests Go Brrrr! : Getting Started with Cypress in ReactJS](https://www.wearedevelopers.com/videos/282-watch-tests-go-brrrr-getting-started-with-cypress-in-reactjs) - [Are Code Reviews Worth It? Insights from 16 Years of Review Data](https://www.wearedevelopers.com/videos/1135-are-code-reviews-worth-it-insights-from-16-years-of-review-data) - [Bringing the power of AI to your application.](https://www.wearedevelopers.com/videos/1010-bringing-the-power-of-ai-to-your-application) - [WebAssembly: The Next Frontier of Cloud Computing](https://www.wearedevelopers.com/videos/972-webassembly-the-next-frontier-of-cloud-computing) ## Related Articles - [Navigating the AI Shift](https://www.wearedevelopers.com/magazine/629-navigating-the-ai-shift) - [What is Software Engineering in the Age of AI?](https://www.wearedevelopers.com/magazine/640-what-is-software-engineering-in-the-age-of-ai) - [Trustworthy AI Starts at Deployment: 5 Checks Before You Ship](https://www.wearedevelopers.com/magazine/753-trustworthy-ai-starts-at-deployment-5-checks-before-you-ship) - [Never delegate the understanding](https://www.wearedevelopers.com/magazine/749-never-delegate-the-understanding) - [Dev Digest 137 - AI'm not sure about this](https://www.wearedevelopers.com/magazine/485-dev-digest-137-ai-m-not-sure-about-this) - [Dev Digest 120 - Apple and peers](https://www.wearedevelopers.com/magazine/455-dev-digest-120-apple-and-peers)