Staff Software Engineer: AI-Driven Product Architect

Factorial Hr; Barcelona; Híbrido; EUR 110.000 - 150.000; Jornada completa

Ventajas ofrecidas por este puesto de trabajo

Private health insurance

Wellhub gym

Cobee benefits

Language classes

Office breakfast

Food discounts Nora

Pet friendly

Descripción de la vacante

Factorial HR is seeking a Staff Software Engineer to help build AI-native features into our product using Rails and React. You will lead technical initiatives, set architecture direction, and ship real features in production, closely partnering with Product and Design.

This hybrid role is based in Barcelona, with on-site collaboration several days a week and remote options when appropriate. You will design scalable systems, integrate LLM APIs, and mentor engineers to raise the bar across the

Formación

• Solid depth in both backend and frontend software engineering.
• Shipped real products to production, not prototypes or proofs of concept.
• Experience with APIs, cloud platforms, and system design.
• Integrated LLM APIs into product features and shipped them to real users.
• Seen as a technical and cultural leader with high standards.
• Push back on non-value-adding processes from hiring to deployment.
• Drive adoption of new abstractions and ensure usability across teams.
• Led key technical decisions and built reusable foundations.
• Clear English communication; Spanish is a plus.

Responsabilidades

• Lead technical initiatives and set architecture direction for meaningful roadmap chunks.
• Collaborate closely with Product and Design from earliest conversations.
• Own systems end to end from problem to production and long-term maintenance.
• Interact with customers to bring context into development decisions.
• Define how to build AI features at scale with reliability and compliance.
• Promote spec-driven development with clear behaviors and edge cases.
• Build reusable components for other product domains to use.
• Design and evolve AI skills and modular capabilities that automate workflows.
• Create tooling to keep AI features trustworthy and observable.
• Ground AI outputs using deterministic data sources for accuracy.
• Mentor others and raise engineering standards across the team.
• Avoid roles focused on model training; focus on AI product engineering.

Conocimientos

Backend & Frontend

APIs & Cloud

LLM API Integration

System Design

Leadership

Communication (Eng)

Herramientas

Ruby on Rails

React

SQL / Databases

LLM Platforms

Descripción del empleo

Factorial HR is seeking a Staff Software Engineer to help build AI-native features into our product using Rails and React. You will lead technical initiatives, set architecture direction, and ship real features in production, closely partnering with Product and Design.

This hybrid role is based in Barcelona, with on-site collaboration several days a week and remote options when appropriate. You will design scalable systems, integrate LLM APIs, and mentor engineers to raise the bar across the