> Markdown version of [/jobs/ext/1692328-founding-full-stack-ai-ml-engineer](https://www.wearedevelopers.com/jobs/ext/1692328-founding-full-stack-ai-ml-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). --- # Founding Full-Stack AI/ML Engineer - **Company:** Cataluña - **Location:** Barcelona, Spain - **Contract:** Permanent contract - **Skills:** Application Programming Interfaces (APIs), Artificial Intelligence, Data Analysis, Cloud Computing, Databases, Customer Data Management, Information Engineering, Web Development, Machine Learning, Open Source Technology, Recommender Systems, Systems Integration, TypeScript, ReactJS, Large Language Models, Model Validation, Backend, Free and Open-Source Software, Front End Software Development - **Published:** July 13, 2026 - **Apply:** https://www.jobleads.com/es/job/e703d70e0189aa0a1124ccc4f7b5d3189 ## About the Role We care more about proof of ability than credentials. You do not need a specific degree, company logo, or background. But you do need to show that you can build hard things. Professional background * Strong full-stack engineering ability. * Experience with TypeScript, React, and modern web development. * Solid understanding of backend systems, APIs, databases, queues, cloud infrastructure, and system design. * Advanced knowledge of machine learning and modern AI systems. * Experience with LLMs, agents, embeddings, retrieval, model evaluation, or applied ML workflows. * Ability to reason from first principles and solve ambiguous technical problems. * Strong product instinct and the ability to build simple, useful, high-quality interfaces. * High ownership, low ego, and strong execution speed., * Experience with customer data, lifecycle marketing, CRM, personalization, recommender systems, or experimentation. * Experience with data engineering, event pipelines, analytics, or decisioning systems. * Experience with enterprise SaaS, B2B products, or integrations-heavy systems. * Open-source work, technical writing, research, demos, or strong personal projects. * Previous founder, early startup, or high-ownership engineering experience., That can be GitHub, projects, demos, technical writing, past work, architecture notes, open-source contributions, or a short note explaining why this problem interests you. ## Description We are looking for a Founding Full-Stack AI/ML Engineer. This is not a narrow frontend role, backend role, or ML research role. We need someone who can move across the stack and turn messy business problems into working software. You will work directly with the founders and help define the product, architecture, engineering culture, and technical direction of the company. You will build product, data, and AI systems that are used with real customer data and real business outcomes. What you will work on * Building full-stack product features across frontend, backend, data, and ML layers. * Designing systems that process customer, event, and behavioral data. * Building AI agents that analyze customer behavior and recommend or execute lifecycle actions. * Creating workflows to monitor agent decisions, performance, reliability, and business impact. * Integrating LLMs, ML models, APIs, customer data platforms, CRMs, and third-party tools. * Building evaluation systems to measure accuracy, edge cases, reliability, and business impact. * Designing backend infrastructure for real-time and batch decisioning. * Building internal tools and dashboards that make complex systems understandable and controllable. * Working directly with customers to understand their workflows and translate them into product. * Shipping fast while keeping the system secure, maintainable, and scalable., This is not a remote or hybrid role. At this stage, speed matters. Context matters. Working side by side matters. We move fast, use AI heavily, and expect everyone on the team to own problems end to end. You will not be handed perfectly scoped tickets forever. You will be expected to understand the problem, think through the product, make technical decisions, build, ship, and improve the system. We are a small team with high standards. Early engineers will have a real impact on what the company becomes. This is an opportunity to join at the earliest stage of a company building a technical product for a large market. You will work on real problems, with real customers, real data, and real business impact. You will help shape the product, architecture, engineering standards, and culture from the beginning. This role is for someone who wants ownership, intensity, and the chance to build something from zero to one. ## Related Videos - [Kubernetes and Microservices with Multi-Model Databases](https://www.wearedevelopers.com/videos/382-kubernetes-and-microservices-with-multi-model-databases) - [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) - [Developing the Backend with Stefan Lingler, CTO at Shpock](https://www.wearedevelopers.com/videos/100360-developing-the-backend-with-stefan-lingler-cto-at-shpock) - [Coffee with Developers - Maria Apazoglou](https://www.wearedevelopers.com/videos/1209-coffee-with-developers-maria-apazoglou) - [Fault Tolerance and Consistency at Scale: Harnessing the Power of Distributed SQL Databases](https://www.wearedevelopers.com/videos/1146-fault-tolerance-and-consistency-at-scale-harnessing-the-power-of-distributed-sql-databases) - [Developer Experience, Platform Engineering and AI powered Apps](https://www.wearedevelopers.com/videos/990-developer-experience-platform-engineering-and-ai-powered-apps) ## Related Articles - [Navigating the AI Shift](https://www.wearedevelopers.com/magazine/629-navigating-the-ai-shift) - [How to Become an AI Engineer](https://www.wearedevelopers.com/magazine/331-how-to-become-an-ai-engineer) - [MLOps – What’s the deal behind it?](https://www.wearedevelopers.com/magazine/125-mlops-what-s-the-deal-behind-it) - [MLOps And AI Driven Development](https://www.wearedevelopers.com/magazine/82-mlops-and-ai-driven-development) - [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)