Barcelona (Only EU Visa Holders) We are looking for the strongest Senior Backend Engineer (Node.Js) in the ecosystem. Not the cheapest. The best. I’m supporting a founding team with a very high technical bar in hiring the person who will define the core architecture of a new AI Agents platform already live, already used by real customers, and with a roadmap that is genuinely ambitious. This is not a generic “backend role”. This is systems design at scale: distributed architectures, agent orchestration, real-time data pipelines, context engineering, agentic memory, advanced RAG, high-performance APIs, and direct collaboration with AI/ML teams to push models into production. What they value: Node.Js + Typescript Cloud-native engineering (AWS/Azure) Docker, Kubernetes, Terraform PostgreSQL & distributed systems Strong API architecture Hands-on experience (or serious interest) with LLMs & agentic workflows Compensation: there is no salary cap. The team is not looking for the cheapest option; they’re looking for thestrongest engineer. For the right person, they will stretch — base, bonus, equity, everything. Add to that: real engineering culture (radical candor, simplicity, velocity), zero politics, meaningful ownership, and the chance to build AI agents that solve real-world problems… all from Barcelona. If you're Senior/Staff level and want to build core systems you don’t get to touch in a normal role, message me. And if you know someone exceptional, I’d really appreciate the referral.