> Markdown version of [/jobs/ext/1954195-software-engineer](https://www.wearedevelopers.com/jobs/ext/1954195-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).

---

# Software Engineer

- **Company:** Factorial
- **Location:** Barcelona, Spain (Remote available)
- **Salary:** €8,320.0
- **Contract:** Permanent contract
- **Skills:** Artificial Intelligence, Ruby on Rails, ReactJS, Large Language Models, Multi-Agent Systems, React Native
- **Published:** August 6, 2026
- **Apply:** https://www.adzuna.es/contact-us.html

## About the Role

Your title matters less than your mindset. You might be senior or staff, what we care about is:

 + Builder mentality: You've built products from 0 before, in a startup or a similarly high-ambiguity environment, and you're energized by that rather than needing a defined roadmap.
 + Adaptability: You're comfortable when priorities change quickly and requirements aren't fully defined yet.
 + Technical range: Fullstack experience (Rails/React/React Native), or deep React Native expertise if you're mobile-focused.
 + AI as a habit: You've built real AI- or agent-powered systems, not just experimented with them.
 + Seniority: Solid experience as a software engineer, comfortable owning ambiguous problems end to end.
 + Communication: Comfortable working in English in a multicultural team.
Bonus points if you've worked with LLMs, agent frameworks, MCP, or other AI protocols.

## Description

We're starting something new at Factorial: Chats. It's a fresh area of the product, built around communication and, from day one, built with AI and agents doing real work in it, not just a chatbot bolted onto the side. There's no team page for this yet. No backlog gathering dust, no "how we've always done it." Just the problem, and whoever shows up to solve it.
We're hiring a Senior or Staff engineer to help get Chats off the ground. Fullstack is ideal, but if your expertise lies merely in mobile it works for us too!
This isn't just a new product, it's a chance to rethink how software gets built. We're creating an AI-native product from scratch, where AI isn't another feature but part of the core architecture and user experience. Every technical and product decision starts with the question: how would we build this if AI existed from day one?
We're looking for engineers with a founder mentality. People who thrive in ambiguity, move quickly, question assumptions, and are excited to create rather than maintain. There won't be years of legacy decisions to work around, only opportunities to shape the product, the platform, and the culture from the ground up.
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.


## Related Videos

- [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)
- [Challenges of building React and React Native apps](https://www.wearedevelopers.com/videos/448-challenges-of-building-react-and-react-native-apps)
- [Coffee with Developers: David Heinemeier Hansson](https://www.wearedevelopers.com/videos/875-coffee-with-developers-david-heinemeier-hansson)
- [You are not an AI developer](https://www.wearedevelopers.com/videos/1148-you-are-not-an-ai-developer)
- [Your next 10x engineer isn't in your city. Refactor accordingly.](https://www.wearedevelopers.com/videos/100103-your-next-10x-engineer-isn-t-in-your-city-refactor-accordingly)
- [Building Better Apps with React Native](https://www.wearedevelopers.com/videos/1466-building-better-apps-with-react-native)

## Related Articles

- [Navigating the AI Shift](https://www.wearedevelopers.com/magazine/629-navigating-the-ai-shift)
- [Dev Digest 120 - Apple and peers](https://www.wearedevelopers.com/magazine/455-dev-digest-120-apple-and-peers)
- [Dev Digest 121 - AI goes offline](https://www.wearedevelopers.com/magazine/456-dev-digest-121-ai-goes-offline)
- [How to Become an AI Engineer](https://www.wearedevelopers.com/magazine/331-how-to-become-an-ai-engineer)
- [Fully Remote Software Engineer Jobs](https://www.wearedevelopers.com/magazine/447-fully-remote-software-engineer-jobs)
- [Why Upskilling And Reskilling is Important For Developers](https://www.wearedevelopers.com/magazine/428-why-upskilling-and-reskilling-is-important-for-developers)