{"id":2142826,"url":"https://alion.io/job/factorial-staff-software-engineer","title":"Staff Software Engineer","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":"C","score":65,"open_postings":125,"ghost_share":0.584,"stale_share":0,"repost_share":0,"time_to_fill_p50_days":null,"computed_at":"2026-10-12T06:55:09Z"}},"role":"Backend","role_family":"Backend","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":["Barcelona, Spain"],"countries":["ES"],"hiring_countries":["ES"],"hiring_countries_total":1,"salary":null,"salary_estimate":{"min_usd":73000,"max_usd":154000,"period":"year","method":"global_role_cell_scaled_by_country","sample_n":2065},"experience_years_min":null,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"AI Agents","optional":false},{"name":"AWS","optional":false},{"name":"Azure","optional":false},{"name":"Fine-tuning","optional":false},{"name":"GCP","optional":false},{"name":"LLM","optional":false},{"name":"React.js","optional":false},{"name":"Agentic Workflows","optional":true},{"name":"Agile","optional":true},{"name":"Human-in-the-Loop","optional":true},{"name":"JavaScript","optional":true},{"name":"Ruby","optional":true},{"name":"Ruby on Rails","optional":true}],"status":"live","first_seen_at":"2026-06-12T00:00:00Z","employer_posted_date":"2026-10-09","last_verified_at":"2026-10-12T11:23:52Z","board_verified":true,"closed_at":null,"days_open":122,"trust":{"level":"ghost","repost_count":0,"flags":["stale","company_stale"],"days_open":122},"description":"Hello!\nWe'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.\nAt 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.\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 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.\nWhat are we looking for?\nYou have solid depth in both backend and frontend software engineering\n\nYou've shipped real products to production, not just prototypes or proofs of concept\n\nYou understand APIs, cloud platforms (AWS, Azure, or GCP), and system design well\n\nYou'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\n\nYou're seen as a technical and cultural leader, and you hold the bar high\n\nYou push back on process that doesn't serve the team, from hiring to deployment\n\nYou drive adoption of new abstractions and make sure others can actually use them\n\nYou've shipped things that made a measurable difference, at work or on the side\n\nYou lead key technical decisions and create things others across the company build on\n\nYou communicate clearly in English; Spanish is a plus\n\nWhat You’ll Be Doing?\nLead 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.\n\nWork 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.\n\nOwn systems end to end. From the first conversation about a problem, through production rollout, to long-term maintenance. Including the unglamorous parts.\n\nStay 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.\n\nHelp 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.\n\nChampion 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.\n\nBuild 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.\n\nDesign 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.\n\nBuild 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.\n\nGround 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.\n\nRaise the bar across the company: Whether it's mentoring, hiring, or pushing for better practices, you'll leave the engineering culture better than you found it\n\nOne 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.\nHow We Work (Barcelona or 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 follows 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":8631,"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":[{"language":"English","level":"All levels","optional":false}]},"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":8,"band":"cold","label":"Long shot","p_open":1,"p_active":0.3,"p_room":0.28,"age_days":122,"expected_fill_days":42,"reasons":["conf:2","stale_co","velocity","ghost","win:tail","crowd:brand"],"computed_at":"2026-10-12T06:55:09Z"},"pay":null,"html_url":"https://alion.io/job/factorial-staff-software-engineer","json_url":"https://alion.io/job/factorial-staff-software-engineer.json","meta":{"generated_at":"2026-10-12T16:05:01Z","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":25626,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-10-13T00:00:00Z"}},"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-software-engineer"},{"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-software-engineer"},{"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-software-engineer"},{"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-software-engineer\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Ffactorial-staff-software-engineer"}]}