Full Stack Engineer

We're looking for a Full Stack Engineer for one of our clients who enjoys building new products from the ground up and is eager to help shape AI tooling for the mobility industry. - Work across the full stack to solve complex problems using incomplete and messy data - Design and evolve canonical data models - Build pipelines to handle real-world data inputs - Define and implement methods to resolve conflicting data - Build and orchestrate agents that reason over data and take action - Design agent behavior, including failure and recovery processes - Create outputs that are explainable and auditable - Ship features from idea through to production - Help shape product direction, not just implement technical decisions - Strong full-stack engineering skills (tech stack experience is flexible) - Comfortable working with ambiguity and messy, inconsistent data - Ability to take problems from concept to shipped solution - Product-oriented mindset, focused on delivering outcomes - Open to forming and revising strong opinions as the project evolves - Demonstrated ability to think creatively and critically about what you build - Ruby on Rails (API) - React / Next.js - Python (data and AI orchestration) - Competitive salary: €40,000 to €80,000 - Meaningful equity - Flexible working (3 days in office) - Barcelona HQ with beachfront location - Generous holiday allowance plus public holidays - Team off-sites in exciting locations