Full Stack Ai Engineer

Intelligence (IAI) at our office in Barcelona. We need someone who can support our technical efforts across the board. Working closely with and directly supporting our CTO, you will move fluidly across the whole stack - from backend and platform engineering, to the LLM and AI pipelines at the core of our product, to the infrastructure that runs it, to the frontend that users touch. This is a hands-on individual-contributor role for someone who is happiest when they can pick up almost any part of the system and make progress on it. We are not looking for a specialist in a single layer. We need a strong generalist: someone who can context-switch, learn quickly, and be trusted to deliver across whatever the week demands. You won't own the architecture, but you will be the person who helps turn it into working, reliable software, and your judgement will carry real weight. We need someone with a strong startup attitude: sharp problem-solving skills, the ability to manage priorities and deliverables autonomously without rigid timeframes, and the capacity to handle diverse task assignments. If you thrive in ambiguity, move fast without sacrificing quality, and can pivot when priorities shift, you're exactly who we're looking for. This role is for someone energised by wearing multiple hats and making an impact without needing a detailed playbook. If that sounds like you, we'd be excited to hear from you. - Contract Type: Permanent - Full Office-Based Work Modality: Monday to Friday from 9:00 to 18:00 at WeWork Glòries Barcelona Duties & Responsibilities - Build, extend, and maintain the backend services and platform logic that power Typewiser. - Write clean, tested, maintainable code, and contribute to the overall health of the codebase. - Implement features end-to-end, from data layer through to API, in collaboration with the CTO. - Develop and integrate the LLM-driven pipelines at the core of the product, including prompting strategies, orchestration, structured outputs, and RAG and validation layers. - Integrate and evaluate third-party AI models and APIs, balancing quality, latency, and cost. - Help build the tooling and evaluation needed to keep AI-driven features reliable and reproducible. Infrastructure & Deployment - Set up, maintain, and improve our deployment pipelines, infrastructure, and environments. - Handle the operational side of running the platform: CI/CD, monitoring, and keeping things stable and secure. Frontend & Full-Stack - Contribute to the frontend and deliver full-stack features as needed, ensuring a coherent experience from interface to backend. - Collaborate on the product's UI where engineering and design meet. Qualifications Required - 5 to 8+ years of professional software engineering experience, with demonstrable full-stack breadth. - Strong backend engineering skills, with proficiency in Python (our primary backend language). - Hands-on experience integrating and working with LLMs or other AI/ML models in production, including prompt engineering. - Working experience with frontend development and modern web frameworks. - Practical experience with infrastructure, deployment, and DevOps practices (CI/CD, cloud environments, containerisation). - A genuine generalist mindset: comfortable owning a problem across the entire stack rather than a single layer. - Ability to work in a fast-paced startup/scale-up environment and understand the specific challenges of early-stage companies. Preferred - Experience with AWS. - Familiarity with RAG architectures, vector databases, and LLM evaluation. - Experience in an early-stage startup, owning broad surface area with limited support. - Exposure to NLP or document-processing systems.