Back End Developer

Senior Backend / Platform Engineer (AI Tooling) Location: Hybrid - 3 days onsite per week, Sant Boi de Llobregat, Catalonia, Spain Type: Full-time Overview We're seeking a skilled Senior Backend / Platform Engineer to help build and scale the backend systems for AI-driven tools in a high-performance product environment. You'll join a fast-paced, ambitious team working on complex backend architecture that powers intelligent services across internal and external platforms. The Role As the lead backend engineer for AI tooling, you’ll be responsible for designing, implementing, and maintaining backend services, primarily supporting AI and data science teams. This includes integrating Python-based machine learning tools into scalable production systems using Node.js and Python. Key Responsibilities Own the design and implementation of AI-powered backend services and APIs Support the operationalisation of ML models and tools into production systems Collaborate cross-functionally with AI engineers, product managers, DevOps, and QA Define coding standards and lead architectural decisions Optimise workflows, challenge legacy systems, and propose backend improvements Troubleshoot and resolve production issues quickly and effectively Mentor junior engineers and foster knowledge sharing Maintain clear and comprehensive documentation in English What We’re Looking For 5 years in backend software development, ideally with Node.js and Python Strong knowledge of data structures, algorithms, and scalable distributed systems Solid experience in RESTful API design and implementation Proficiency in SQL, schema design, and query optimisation Understanding of modern backend architectures (microservices, CQRS, event-driven systems) Ability to work independently and drive initiatives forward Fluent in English, with excellent communication and documentation skills Growth mindset and team-first attitude Bonus Points Experience with cloud infrastructure (AWS), Docker, Kubernetes, and CI/CD Familiarity with machine learning/AI concepts such as LLMs, agents, or RAG Exposure to Python-based ML tooling Experience with document databases like MongoDB Background in end-to-end technical projects and architecture planning

Location: Sant Boi de Llobregat, Catalonia, ES

Posted Date: 8/2/2025