ppHello! /ppWe're looking for a Staff Software Engineer to help build AI-native features into Factorial's product. Not a researcher, not a model trainer: a product engineer who builds with LLM APIs the same way we build with any other API, shipping real features to real customers in production. /ppAt Factorial, being a Staff Engineer means leading technical initiatives and working very closely with Product, not operating at arm's length from the roadmap. You'll be writing Rails and React, designing systems, and shipping product hand in hand with Product and Design. "AI" is the domain you'll work in, not a different job. /ppReady to be part of the challenge? /ph3About the team /h3pOur 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. /ppWe'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. /ph3What are we looking for? /h3ulliYou have solid depth in both backend and frontend software engineering /liliYou've shipped real products to production, not just prototypes or proofs of concept /liliYou understand APIs, cloud platforms (AWS, Azure, or GCP), and system design well /liliYou've integrated LLM APIs into product features and shipped them to real users. This is about building with AI, not training or fine-tuning models /liliYou're seen as a technical and cultural leader, and you hold the bar high /liliYou push back on process that doesn't serve the team, from hiring to deployment /liliYou drive adoption of new abstractions and make sure others can actually use them /liliYou've shipped things that made a measurable difference, at work or on the side /liliYou lead key technical decisions and create things others across the company build on /liliYou communicate clearly in English; Spanish is a plus /li /ulh3What You’ll Be Doing? /h3ulliLead technical initiatives. As a Staff Engineer, you'll set technical direction for meaningful chunks of the roadmap, not just execute against it. You'll make the calls on architecture and approach, and be accountable for how they play out. /liliWork very closely with Product. This isn't occasional collaboration, it's a tight, ongoing partnership. You'll shape what gets built alongside Product and Design from the earliest conversations, not just take specs and implement them. /liliOwn systems end to end. From the first conversation about a problem, through production rollout, to long-term maintenance. Including the unglamorous parts. /liliStay close to customers. The best technical decisions come from understanding real problems,



so you'll talk to customers directly and bring that context back into how we build. /liliHelp define how we build AI features at scale. We're still figuring out what great AI product engineering looks like at Factorial, and that's part of the job. You'll help shape how we design, build, and run AI-native product experiences so they're reliable, compliant, and genuinely useful. /liliChampion spec-driven development. Push for a culture where teams define what "good" looks like before they build: expected behaviors, constraints, edge cases, success criteria. Then use those specs to move fast without breaking things. /liliBuild things other teams can reuse. Rather than a patchwork of one-off AI experiments, you'll build shared components other product domains can actually use: scalable, secure, and easy to govern. /liliDesign and evolve AI Skills. Drive the creation of modular, reusable AI "skills" that automate real workflows and take safe, traceable actions inside Factorial's ecosystem, especially where finance is involved. /liliBuild the tooling that keeps AI features trustworthy. Getting an AI feature to production is one thing. Keeping it reliable once real customers depend on it is another. You'll build monitoring and quality tooling (automated and human-in-the-loop) so teams get a real signal on quality. /liliGround AI features in data we actually trust. Help define how we combine LLM outputs with deterministic sources of truth, balancing flexibility with accuracy and compliance. /li /ulh3Raise the bar across the company /h3pWhether it's mentoring, hiring, or pushing for better practices, you'll leave the engineering culture better than you found it /ppOne honest note: if you're mainly looking to do model training, fine-tuning, or applied ML research, this probably isn't the right role for you. We're a product engineering team working with LLM APIs and agentic systems, not a team building models from scratch. /ph3How We Work (Barcelona or Madrid Office) /h3pAt 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, adaptable schedule. /ppWe 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. /ppThis balance helps us stay agile, creative, and closely connected,



while giving everyone the space to do their best work. /ppAt Factorial we don't evaluate you by years of experience but by your knowledge and skills. /ppWe 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. /ph3Our Hiring Process /h3ulliIntro Call → Chat with our Talent Partner about your journey and goals. /liliHiring Manager Interview → Deep dive into your product mindset, teamwork, and problem-solving. /liliLive Challenge → A collaborative technical exercise based on real-life problems. /liliFinal Coffee Chat → A relaxed conversation with our CTO VP of Engineering to explore our vision, culture, and your growth. /li /ulpThe whole process is remote, using videoconferencing tools! /ph3About Factorial /h3pAt Factorial we're building the leading AI Business Management Software for companies of all sizes. Our platform centralizes key workflows across HR, Finance, Talent, Operations, and IT, freeing teams from manual processes so they can focus on what really matters: leading, growing, and taking care of their people. With over 1,500 employees across Europe, Asia, Africa, and America. We are one of Europe’s fastest-growing SaaS companies, proudly headquartered in Barcelona. If you're excited to shape the future of business management technology, we'd love to meet you. /ppWe believe in diverse talent: we welcome applicants from all backgrounds and strongly encourage people of diverse experiences and identities to apply. /ppWe believe in inclusion: we are committed to equal opportunities and actively promote workplace inclusion of people with disabilities. If you would like to learn more about our inclusive recruitment processes, you are welcome to indicate so optionally and we will share additional information with you. /ph3Our Values /h3ulliWe own it: We take responsibility for every project. We make decisions, not excuses. /liliWe learn and teach: We're dedicated to learning something new every day and, above all, share it. /liliWe partner: Every decision is a team decision. We trust each other. /liliWe grow fast: We act fast. We think that the worst mistake is not learning from them. /li /ulpWanna learn more about us? Check our website! /ph3Perks of being part of Factorial /h3ulliHigh growth, multicultural and friendly environment /liliAlan as private health insurance /liliHealthy life with Wellhub (Gyms, pools, outdoor classes) /liliSave expenses with Cobee /liliLanguage classes /liliBreakfast in the office and organic fruit /liliFood discounts with Nora /liliPet Friendly /liliMuch more that we'll spill during the interview process! /li /ul /p #J-18808-Ljbffr

📌 Staff Software Engineer (Barcelona)
🏢 Factorial Hr
📍 Barcelona