AI Staff Engineer - Operations Domain

We’re looking for Staff Engineers who:

• Treat AI as central to their craft
• Are obsessed with building and shipping fast
• Care about real impact, not hierarchy or titles

If that sounds like you, keep reading.

The Team

The Operations domain sits at the core of Factorial. This is where we build the systems that run the day-to-day reality of work for thousands of companies, systems that must be accurate, compliant and reliable.

Our teams own business-critical workflows such as:

• How employee time is tracked, planned, and managed
• How the employee journey is modeled from onboarding to offboarding
• How companies represent their organizational structure
• How compensation and payroll data are calculated and trusted.
• Our mission is to turn operational complexity into simple, AI-powered experiences, helping companies run smoothly at scale while keeping humans in control of what matters most.

What you’ll do as a Staff Engineer in AI

Define how we build AI at scale

Drive the evolution of modern AI development practices across the organization. You’ll help establish how we design, build, evaluate, and operate AI-native product experiences, ensuring they are reliable, compliant, and aligned with business outcomes.

Lead Spec-Driven Development for AI

Promote a culture of defining clear specifications before shipping, including expected behaviours, constraints, risk boundaries, and measurable success criteria. You’ll guide teams in using these specs to iterate safely and efficiently with the most powerful LLMs.

Build reusable AI foundations

Design and implement shared AI capabilities and abstractions that can be adopted across multiple product domains. You’ll focus on creating scalable, secure, and well-governed systems rather than isolated features.

Design and evolve AI Skills

Drive the creation of modular, reusable AI “skills” that can automate real workflows and take safe, auditable actions within Factorial’s ecosystem, especially in finance-critical contexts.

Establish robust evaluation frameworks

Lead the development of automated and human-in-the-loop evaluation systems to measure quality, correctness, safety, and reliability. You’ll help teams move from experimentation to production-grade AI.

Shape Retrieval-Augmented Generation strategies

Define how we ground AI systems in trusted company and customer data. You’ll balance probabilistic models with deterministic sources of truth, ensuring scalability, compliance, and accuracy.

Design human-in-the-loop and agentic workflows

Architect systems that combine LLMs, rules, and user oversight. You’ll enable automation while ensuring transparency, control, and regulatory alignment in critical business processes.

Own systems end-to-end

Lead initiatives from problem definition and system design to production rollout, monitoring, and continuous improvement. You’ll focus on long-term maintainability and organizational leverage.

Stay deeply connected to customers

Promote a strong customer-centric engineering culture. You’ll engage with customers directly to understand real workflows, risks, and constraints, ensuring we solve meaningful problems.

Partner with Product, Design, and Leadership

Collaborate cross-functionally to embed AI into core product experiences. You’ll influence roadmap decisions and ensure AI is integrated as a fundamental part of workflows.

Raise the bar across the company

Mentor engineers, contribute to hiring and technical growth, and define best practices that elevate Factorial’s engineering culture and AI maturity.

Do you have experience in Scalability?, * Proven impact: shipped projects, side projects, or contributions that made a measurable difference

• Product-first thinking: you design complete experiences, not just isolated components
• Speed & adaptability: you experiment, learn, and iterate fast.

Strong Staff Engineers at Factorial have:

• Very solid software engineering expertise in both backend and frontend.
• Experience with cloud platforms, such as AWS, Azure, or Google Cloud Platform.
• Experience shipping real products to production.
• Knowledge of APIs, cloud platforms, and system design
• Are seen as leaders technically and culturally, maintaining high-quality standards.
• Challenge engineering processes, from hiring to code deployment.
• Drive adoption of new abstractions, creating supporting ecosystems like documentation and metrics.
• Lead key technical decisions and creates company-wide abstractions.
• Excellent communication skills in English; knowledge of other languages is a plus, specially Spanish.

We care about people and we also offer a lot of benefits for employees:

• High growth, multicultural and friendly environment
• Alan private health insurance
• Healthy life with Wellhub (Gyms, pools, outdoor classes)
• Save expenses with Cobee
• Language classes
• Breakfast in the office and organic fruit
• Nora discounts
• Free caffeine and theine

The hiring process

If you apply, here’s what to expect:

• A first conversation with our Talent Acquisition Partner. It will be about comparing our expectations and making sure we match on a human level. We will also check our Engineering Rubrics (check them out, they are open!) and the salary in your position.

• A second conversation with the team’s Engineering Manager. This is about making sure we can work together. Here you will have a conversation about the team, their needs, your profile and how can you complement it. Expect to have a mix of a human and technical conversation.

A Live Engineering Challenge with two Factorial engineers: At Factorial, we’re passionate about hiring engineers who can think clearly, communicate well, leverage the best tools, and learn very fast. In this challenge, we’re not looking for a finished product, but for how you structur…

At Factorial, we’re building the leading business management software for companies of all sizes. Our platform centralizes key workflows across HR, finance, and operations, freeing teams from manual processes so they can focus on what really matters: leading, growing, and taking care of their people.With over 1,200 employees across 7 markets, we serve 700,000+ users and are one of Europe’s fastest-growing SaaS companies, backed by top-tier investors and proudly headquartered in Barcelona.We believe in bold goals, radical ownership, and inclusive collaboration. If you’re excited to shape the future of business management technology, we’d love to meet 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.
• 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.