{"id":2142972,"url":"https://alion.io/job/factorial-staff-ai-engineer-api-integrations-team-madrid","title":"Staff AI Engineer - API & Integrations Team (Madrid)","company":{"id":53702,"name":"Factorial","domain":"factorialhr.com","url":"https://alion.io/company/factorial","size_band":"51-200","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Factorial","truth_index":{"grade":"A","score":95,"open_postings":120,"ghost_share":0,"stale_share":0,"repost_share":0,"time_to_fill_p50_days":641,"computed_at":"2026-10-20T05:45:00Z"}},"role":"AI/ML","role_family":"AI/ML","seniority":"staff","employment_type":null,"work_mode":"remote","remote_scope":"stated_countries","remote_scope_basis":"board_field","remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["Madrid, Spain"],"countries":["ES"],"hiring_countries":["ES"],"hiring_countries_total":1,"salary":null,"salary_estimate":{"min_usd":75000,"max_usd":172000,"period":"year","method":"global_role_cell_scaled_by_country","sample_n":1192},"experience_years_min":null,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"Agentic Workflows","optional":false},{"name":"RAG","optional":false},{"name":"React.js","optional":false},{"name":"Ruby on Rails","optional":false},{"name":"Agile","optional":true},{"name":"JavaScript","optional":true},{"name":"Model Context Protocol","optional":true},{"name":"Ruby","optional":true}],"status":"live","first_seen_at":"2026-07-13T00:00:00Z","employer_posted_date":"2026-10-09","last_verified_at":"2026-10-20T14:25:28Z","board_verified":true,"closed_at":null,"days_open":99,"trust":{"level":"ok","repost_count":0,"flags":["company_stale"],"days_open":99},"description":"Hello!\nDo you want to help us build the platform that connects Factorial to the rest of the software world, with strong engineering foundations today and AI as a growing part of how we work tomorrow?\nWe're looking for engineers who:\nCare about the maturity and quality of what they ship, more than the specific stack they use\n\nCare about whether the thing they built actually worked - not what their title says\n\nReady to be part of the challenge?\nAbout the team\nOur 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.\nWe're a team of 200+ Product Engineers building a Business Management solution that actually works for the people using it. Our core stack is Ruby on Rails and React, though we're open to engineers from other stacks - what matters most to us is the maturity of your development practice.\nThe API & Integrations team addresses particular challenges at Factorial. We sit at the intersection between product and platform. We own product surface while we also design developer experiences for internal and external developers of integrations.\nWe build tools for Factorial product teams to publish in our extensive public API.\n\nWe build an integrations framework to achieve the best user experience and developer experience when using integrations. Several Factorial products are already using this framework, and we keep expanding it.\n\nWe enable our developer partners to extend Factorial and live the best developer experience. With the acquisition of YepCode, we're laying the groundwork to bring AI further into how we build integrations.\n\nOur mission is not only to unblock markets that rely on a fragmented market of different external software (payroll software solutions, ERPs, cloud-based identity services, etc.), but also to lower the barrier so that anybody (even HR managers) is able to create new integrations.\nWhat You'll Do\nAs an engineer on the API & Integrations team, your main focus will be owning the development of our public API and integrations framework end-to-end, from problem definition and system design to shipping, monitoring, and iteration in production.\nYou will:\nOwn systems end-to-end\nFrom problem definition and system design to shipping, monitoring and iteration in production.\n\nCollaborate closely with Product and Design\nShape how the API and integrations framework serve real user needs, not just isolated technical components.\n\nWork with a real cross-product consistency challenge: keeping the same user and integration experience across verticals (ATS, payroll, ERPs...), all tied to Factorial's design system and transparent to every product team.\n\nStay close to our customers\nWe have a strong customer-centric mindset: engineers regularly join customer calls, reviews, and feedback sessions to deeply understand real workflows, pain points, and constraints, ensuring we build the right solutions to real problems, not assumptions.\n\nShare knowledge and raise the bar\nMentor peers, document learnings, and contribute to Factorial's engineering best practices.\n\nTake ownership of AI as it takes shape\nAs we build on the YepCode acquisition, you won't be joining a finished AI roadmap, you'll be one of the people defining it: AI Skills, evaluation frameworks (Evals), RAG, and agentic workflows are all still taking shape, and we want someone who wants to build them, not just use them.\n\nWhat are we looking for?\nYour title matters less than your mindset.\nYou might be mid, senior, or staff. What we care about is:\nDevelopment maturity: you write solid, well-tested, production-grade code and can be trusted to own a system end-to-end\n\nProven impact: shipped projects, side projects, or contributions that made a measurable difference\n\nProduct-first thinking: you design complete experiences, not just isolated components\n\nSpeed & adaptability: you experiment, learn, and iterate fast\n\nAn abstraction mindset: real experience working with legacy/monolithic systems, with a track record of thinking in reusable, generic frameworks and components that serve multiple teams and languages, abstracting and generalizing solutions for multiple cases, rather than one-off, product-specific fixes.\n\nBonus points if you've worked with:\nLLMs, skill-based agents, MCP, or other AI protocols are not required today, but relevant as our roadmap evolves.\nTechnical Foundation (Not Strict Requirements)\nStrong candidates often have:\nSolid software engineering fundamentals and development maturity, in any language (backend, frontend, or both)\n\nExperience shipping real products to production\n\nKnowledge of APIs, cloud platforms, and system design\n\nA fast learning curve with new tools and technologies\n\nWe care far more about what you've built than the stack you used. Our team currently works with Ruby on Rails and React, but we're open-minded about candidates from other stacks. We're specifically looking for prior experience working with legacy/monolithic systems and evolving internal frameworks; the language itself doesn't matter, what matters is having gone through that kind of architectural challenge.\nHow We Work (Madrid Office)\nAt 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 follow an office-first, flexible schedule.\nWe 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.\nThis balance helps us stay agile, creative, and closely connected, while giving everyone the space to do their best work.\nAt Factorial we don't evaluate you by years of experience but by your knowledge and skills.\nWe 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.\nOur Hiring Process\nIntro Call → Chat with our Talent Partner about your journey and goals.\n\nHiring Manager Interview → Deep dive into your product mindset, teamwork, and problem-solving.\n\nLive Challenge → A collaborative technical exercise based on real-life problems.\n\nFinal Coffee Chat → A relaxed conversation with our CTO & VP of Engineering to explore our vision, culture, and your growth.\n\nThe whole process is remote, using videoconferencing tools!\nAbout Factorial\nFactorial is the AI for Business that knows companies, connects how work happens across the business, and turns that context into action.\nFounded in Barcelona in 2016, we now have +1,700 employees serving more than 16,000 companies across 112 countries.\nFactorial started with a simple idea: companies were spending too much time managing processes and not enough time doing the work they were hired to do: their best work.\nBut as companies grow, work gets more disconnected. More people, more tools, more information, and more time spent connecting the dots. Generic AI can answer questions, but it doesn’t know your company. Every time, you have to give it the context.\nFactorial is different. Because it’s inside the company, it already knows how it works, including its people, processes, policies, and data. So you can ask it to do real work, from screening candidates and managing expenses to answering questions and creating reports.\nAI isn’t the goal. Giving people back their time is.\nWhen work changes, so do we.\nWe believe in diverse talent: we welcome applicants from all backgrounds and strongly encourage people of diverse experiences and identities to apply.\nWe 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.\nOur Values\nWe own it: We take responsibility for every project. We make decisions, not excuses.\n\nWe learn and teach: We're dedicated to learning something new every day and, above all, share it.\n\nWe partner: Every decision is a team decision. We trust each other.\n\nWe grow fast: We act fast. We think that the worst mistake is not learning from them.\n\nWanna learn more about us? Check our website!\nPerks of being part of Factorial\nHigh growth, multicultural and friendly environment\n\nCompetitive ESOP plan\n\nAlan as private health insurance\n\nHealthy life with Wellhub (Gyms, pools, outdoor classes)\n\nSave expenses with Cobee\n\nLanguage classes\n\nBreakfast in the office and organic fruit\n\nFood discounts with Nora\n\nPet Friendly\n\nMuch more that we'll spill during the interview process!","description_format":"text","description_chars":9057,"description_truncated":false,"requirements":{"experience_years_min":null,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":null,"security_clearance":false,"languages":[]},"benefits":["Flexible schedule","Health insurance","Pet friendly"],"hiring_locations":[{"name":"Spain","iso":"ES","kind":"country"}],"hiring_excludes":[],"relocation_offered":false,"industries":["Artificial Intelligence","Professional Services","Software","Payroll Services"],"lifecycle":[{"event":"open","at":"2026-10-09T03:51:17Z"}],"visa":[],"liveness":{"score":72,"band":"hot","label":"Hiring now","p_open":1,"p_active":0.903,"p_room":0.8,"age_days":99,"expected_fill_days":641,"reasons":["conf:0","velocity","win:early","crowd:brand"],"computed_at":"2026-10-20T05:45:00Z"},"pay":null,"html_url":"https://alion.io/job/factorial-staff-ai-engineer-api-integrations-team-madrid","json_url":"https://alion.io/job/factorial-staff-ai-engineer-api-integrations-team-madrid.json","meta":{"generated_at":"2026-10-20T18:03:08Z","cache_seconds":300,"methodology":"https://alion.io/methodology","terms":"https://alion.io/terms","contact":"https://alion.io/contact","api":"https://alion.io/developers","about":"Alion is a live layer of people, companies and AI agents: who they are, whether they are real and active right now, what they do and how to work with them, readable by people and by agents and paid per call.","catalog":"https://alion.io/catalog.json","usage":{"tier":"crawler_verified","counted_by":"address","units_charged":1,"used_today":20630,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-10-21T00:00:00Z"}},"offers":[{"id":"company.slices","title":"One company in depth, by slice","status":"live","price":{"credits":0.02,"usd":0.002,"plus_per_slice":{"credits":0.05,"usd":0.005}},"unit":"per company, plus each slice with data","note":"the employer in depth","call":{"mcp_tool":"get_company","arguments":{"id":53702},"rest":"https://alion.io/mcp/rest/get_company?id=53702"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Ffactorial-staff-ai-engineer-api-integrations-team-madrid"},{"id":"market.stats","title":"A market slice: pay, demand and time to fill","status":"live","price":{"credits":1,"usd":0.1},"unit":"per slice","note":"pay, demand and time to fill for this role and place","call":{"mcp_tool":"market_stats"},"human":"https://alion.io/catalog?offer=market.stats&for=job%2Ffactorial-staff-ai-engineer-api-integrations-team-madrid"},{"id":"job.search","title":"Open jobs by role, technology, place, pay and visa","status":"live","price":{"credits":0.02,"usd":0.002},"unit":"per posting in a list","note":"similar open postings","call":{"mcp_tool":"search_jobs"},"human":"https://alion.io/catalog?offer=job.search&for=job%2Ffactorial-staff-ai-engineer-api-integrations-team-madrid"},{"id":"company.verify","title":"Is this company real and active right now","status":"pilot","price":null,"unit":"per company","request":{"url":"https://alion.io/catalog/request","method":"POST","body":"{\"offer\": \"company.verify\", \"for\": \"job/factorial-staff-ai-engineer-api-integrations-team-madrid\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Ffactorial-staff-ai-engineer-api-integrations-team-madrid"}]}