> Markdown version of [/jobs/ext/3110648-staff-software-engineer](https://www.wearedevelopers.com/jobs/ext/3110648-staff-software-engineer). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md).

---

# Staff Software Engineer

- **Company:** Factorial Hr
- **Location:** Barcelona, Spain
- **Contract:** Permanent contract
- **Skills:** Application Programming Interfaces (APIs), Artificial Intelligence, Amazon Web Services, Microsoft Azure, Software Engineering, Systems Integration, ReactJS, Large Language Models, Backend, Front End Software Development
- **Published:** September 27, 2026
- **Apply:** https://www.buscojobs.com.es/staff-software-engineer-en-barcelona-ID-372633270

## About the Role

engineering with LLM APIs Responsabilidades * Solid depth in both backend and frontend software engineering * Experience shipping real products to production * Understanding of APIs, cloud platforms (AWS, Azure, or GCP), and system design * Experience integrating LLM APIs into product features and shipping to users * Proven leadership and ability to influence technical direction and culture * Ability to advocate for effective processes, hiring, and deployment practices * Experience building scalable, secure, and governable components * Clear English communication; Spanish a plus Requisitos principales * Alan private health insurance * Wellhub fitness benefits * Cobee expense management * Language classes * Breakfast in the office and organic fruit * Pet friendly workplace

## Description

Experteer Overview As a Staff Software Engineer at Factorial, you will shape AI-native features from end to end, collaborating closely with Product, Design, and Engineering to ship production-ready capabilities.You'll work with Rails and React, designing scalable systems and guiding technical direction for meaningful roadmap areas.You'll lead cross-functional initiatives to build reusable AI components and reliable, compliant product experiences.This role offers impact across a fast-growing, mission-driven company building with LLM APIs and agentic workflows.Compensaciones / Beneficios * Set technical direction for meaningful roadmap chunks and make architecture decisions * Collaborate tightly with Product and Design from the earliest planning stages * Own end-to-end systems from problem to production rollout and long-term maintenance * Engage with customers to capture real problems and feed context back into solutions * Define how to build AI features at scale, ensuring reliability and compliance * Promote spec-driven development with clear success criteria and edge-case handling * Create reusable components and abstractions usable by other teams * Design and evolve modular AI skills that automate workflows and ensure safe actions * Build monitoring and quality tooling (automatic and human-in-the-loop) * Ground AI outputs in trusted data sources, balancing flexibility and determinism * Raise engineering culture through mentoring and better practices * Avoid roles focused on model training or fine-tuning as this is product engineering with LLM APIs Responsabilidades * Solid depth in both backend and frontend software engineering * Experience shipping real products to production * Understanding of APIs, cloud platforms (AWS, Azure, or GCP), and system design * Experience integrating LLM APIs into product features and shipping to users * Proven leadership and ability to influence technical direction and culture * Ability to advocate for effective processes, hiring, and deployment practices * Experience building scalable, secure, and governable components * Clear English communication; Spanish a plus Requisitos principales * Alan private health insurance * Wellhub fitness benefits * Cobee expense management * Language classes * Breakfast in the office and organic fruit * Pet friendly workplace


## Related Videos

- [Developer Tools for Microsoft Azure](https://www.wearedevelopers.com/videos/450-developer-tools-for-microsoft-azure)
- [Developing the Backend with Stefan Lingler, CTO at Shpock](https://www.wearedevelopers.com/videos/100360-developing-the-backend-with-stefan-lingler-cto-at-shpock)
- [Watch Tests Go Brrrr! : Getting Started with Cypress in ReactJS](https://www.wearedevelopers.com/videos/282-watch-tests-go-brrrr-getting-started-with-cypress-in-reactjs)
- [Command and Conquer: How we let an LLM control our Software](https://www.wearedevelopers.com/videos/2056-command-and-conquer-how-we-let-an-llm-control-our-software)
- [Develop enterprise-ready applications for Microsoft Teams with Azure resources on modern web technologies](https://www.wearedevelopers.com/videos/187-develop-enterprise-ready-applications-for-microsoft-teams-with-azure-resources-on-modern-web-technologies)
- [Nest.js - TypeScript in the backend can also be clean](https://www.wearedevelopers.com/videos/1033-nest-js-typescript-in-the-backend-can-also-be-clean)

## Related Articles

- [Spanish Business Culture and Etiquette](https://www.wearedevelopers.com/magazine/353-spanish-business-culture-and-etiquette)
- [Fully Remote Software Engineer Jobs](https://www.wearedevelopers.com/magazine/447-fully-remote-software-engineer-jobs)
- [Dev Digest 121 - AI goes offline](https://www.wearedevelopers.com/magazine/456-dev-digest-121-ai-goes-offline)
- [Dev Digest 120 - Apple and peers](https://www.wearedevelopers.com/magazine/455-dev-digest-120-apple-and-peers)
- [Software Engineer Salary London](https://www.wearedevelopers.com/magazine/252-software-engineer-salary-london)
- [Why Upskilling And Reskilling is Important For Developers](https://www.wearedevelopers.com/magazine/428-why-upskilling-and-reskilling-is-important-for-developers)