Senior Product Engineer - Finance Domain
The posting does not state a salary. This range is our estimate from the role, the location and the stack — treat it as a guide, not an offer.
- Level
- Senior
- Apply from
- Spain
About the role
- Build and ship AI-powered features in Finance.
- Design systems and define architecture for scalability.
- Collaborate with multi-agent systems for coherent outputs.
- Evaluate and measure AI features in production.
- Work in a fast-paced environment with a focus on impact.
Skills the posting asks for
- Ruby on Rails
- React
- AI
- JavaScript
Summarised from the employer’s posting, which is reproduced in full below.
The employer’s full posting
Hello!
Do you want to help us redefine how AI powers the future of Business Management software, not as an add-on, but as a core part of how people work, decide and grow?
We’re looking for engineers who:
As a Product Engineer you’ll help us support and scale our AI- Driven Finance Domain to the next level. Someone who gets involved from problem definition through to measuring whether the thing shipped actually helped, not someone who picks up a ticket, writes the code, and moves on. We want people who are curious about why a feature exists, not just how to build it.
This is not a maintenance role. We're moving fast, the domain is expanding, and there's real engineering work to do.
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.
Finance is one of the fastest-growing domains at Factorial. Its mission is to be the financial backbone of the companies we serve, handling everything from expenses and invoices to payments, cards, accounting, and analytics so that teams can stop chasing paperwork and processes and focus on the decisions that actually move their business. Where we're going is more ambitious. We're building an AI platform that does the work for you: instead of processing invoices, you oversee a system that reconciles them, negotiates amendments with vendors, and closes out the payment cycle on its own. We're extending our banking-as-a-service platform so companies don't just pay with cards and transfers but also get paid, through products like accounts receivable. And we're turning Finance into an engine for cost reduction: planning headcount, policing spend, catching anomalies in invoices and contracts before money goes out, and surfacing the true cost of projects to protect margins. It's a domain where the work has a direct, measurable impact on every company that uses us and where there's a lot still to build!
What are we looking for? 🎯
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 approach.
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
About Factorial 🚀
At 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.
We believe in diverse talent: we welcome applicants from all backgrounds and strongly encourage people of diverse experiences and identities to apply.
We 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.
Our Values
Perks of being part of Factorial 😎
Do you want to help us redefine how AI powers the future of Business Management software, not as an add-on, but as a core part of how people work, decide and grow?
We’re looking for engineers who:
- Treat AI as central to their craft, not a feature to bolt on later
- Want to build and ship, not debate and document
- Care about whether the thing they built actually worked — not what their title says.
As a Product Engineer you’ll help us support and scale our AI- Driven Finance Domain to the next level. Someone who gets involved from problem definition through to measuring whether the thing shipped actually helped, not someone who picks up a ticket, writes the code, and moves on. We want people who are curious about why a feature exists, not just how to build it.
This is not a maintenance role. We're moving fast, the domain is expanding, and there's real engineering work to do.
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.
Finance is one of the fastest-growing domains at Factorial. Its mission is to be the financial backbone of the companies we serve, handling everything from expenses and invoices to payments, cards, accounting, and analytics so that teams can stop chasing paperwork and processes and focus on the decisions that actually move their business. Where we're going is more ambitious. We're building an AI platform that does the work for you: instead of processing invoices, you oversee a system that reconciles them, negotiates amendments with vendors, and closes out the payment cycle on its own. We're extending our banking-as-a-service platform so companies don't just pay with cards and transfers but also get paid, through products like accounts receivable. And we're turning Finance into an engine for cost reduction: planning headcount, policing spend, catching anomalies in invoices and contracts before money goes out, and surfacing the true cost of projects to protect margins. It's a domain where the work has a direct, measurable impact on every company that uses us and where there's a lot still to build!
What are we looking for? 🎯
- 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.
- You'll spend more time designing systems than writing syntax. That means breaking down complex tasks, defining architecture, and writing high-level prompts that instruct multi-agent systems to generate the underlying code.
- You review and validate what the agents produce. Security, scalability, structure — that responsibility sits with you, not the model.
- You'll work on orchestrating multiple AI agents running in parallel, keeping them in sync and making sure the output is coherent across the whole feature.
- There's no established playbook for a lot of this. You'll define your own workflows, experiment, and share what works — because the team moves fast enough that information silos are a real risk.
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 approach.
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
- Intro Call → Chat with our Talent Partner about your journey and goals.
- Hiring Manager Interview → Deep dive into your product mindset, teamwork, and problem-solving.
- Live Challenge → A collaborative technical exercise based on real-life problems.
- Final Coffee Chat → A relaxed conversation with our CTO & VP of Engineering to explore our vision, culture, and your growth.
About Factorial 🚀
At 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.
We believe in diverse talent: we welcome applicants from all backgrounds and strongly encourage people of diverse experiences and identities to apply.
We 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.
Our Values
- We own it: We take responsibility for every project. We make decisions, not excuses.
- We learn and teach: We're dedicated to learning something new every day and, above all, share it.
- We partner: Every decision is a team decision. We trust each other.
- We grow fast: We act fast. We think that the worst mistake is not learning from them.
Perks of being part of Factorial 😎
- High growth, multicultural and friendly environment
- Alan as private health insurance
- Healthy life with Wellhub (Gyms, pools, outdoor classes)
- Save expenses with Cobee
- Language classes
- Breakfast in the office and organic fruit
- Food discounts with Nora
- Pet Friendly
- Much more that we'll spill during the interview process!