Senior Product Engineer

Leadtech Group builds and scales digital products used by millions of people worldwide . With over 18 years of experience , we bring together multidisciplinary teams to turn ideas into meaningful, high-impact solutions. Within the group, MAU by Leadtech focuses on subscription-based apps and digital products. It builds on the expertise, technology and product mindset developed at Leadtech, combining proven experience with a strong focus on user value and long-term growth. Across both brands, we share the same approach: a deep commitment to understanding people and creating experiences that make a difference — for our users and for our teams. We work as a remote-first, international team, where flexibility and collaboration shape how we build, learn and move forward together. Our environment brings together experienced professionals across product, tech, data and design, all driven by curiosity, ownership and continuous improvement. If you’re looking to contribute to products with real impact and grow alongside a team that values how things are built as much as what is built, we’d love to meet you. As part of the AI-LAB team of MAU, as a Senior Product Engineer , you will be instrumental in building a multiplatform AI-powered document system serving hundreds of thousands of users every month. We need a Product Engineer who ships end-to-end: someone who thinks like a product owner, codes like a craftsperson, and reaches for AI-native tooling by default. Build and maintain the core multiplatform document system. You’ll own features end-to-end, from idea to production, React frontends, Node.js/Express backends, and PostgreSQL. Ship to learn. Proactively instrument features, measure impact, seek user feedback, and iterate or kill based on what you discover. You treat metrics as a compass, not a report card. Design and orchestrate agentic AI workflows using modern frameworks (LangGraph, Claude Agent SDK, MCP protocols) and integrate LLMs into product features via prompt chains, tool calling, and function execution. Collaborate with engineers, designers, and leadership to shape the product roadmap. You’ll have a real voice in what gets built and why. Build, maintain, and extend automation pipelines and connect them with AI agents, external APIs, webhooks, and cloud services on GCP. What You Will Bring Python fluency, you can quickly build and utilise a wide range of libraries when the task calls for it. 2–5 years of full-stack experience in a high-output team. You know how to balance speed with quality and when to choose one over the other. Deep TypeScript & React proficiency on the frontend (Hooks, Context API, Vite, Shadcn UI) and backend (Node.js, Express, REST APIs, PostgreSQL). You have taste. You can distinguish between good and bad UX, and you can share examples to demonstrate it. You’re AI-native. You reach for agents by default, understand MCP and agentic orchestration patterns, and have built guardrails to trust them more and more. Python proficiency for rapid prototyping is a must. You’re self-driven and business-aware. You care about solving real problems and moving the needle on metrics, not just shipping features. Give you context, and you’ll find the leverage Bonus Points Previous hands-on experience with LLMs in production, prompt tuning, RAG pipelines, vector databases (Pinecone, Weaviate), or agentic frameworks (LangGraph, CrewAI). Familiarity with LLM observability tools (Langfuse, LangSmith) and cloud platforms (GCP). A genuine passion for AI and a habit of staying on the frontier: new models, protocols (MCP, A2A), and developer tooling. Growth and career development We prioritize your growth. Enjoy a flexible career path with personalized internal training and an annual budget for external learning opportunities. Work-Life balance Benefit from a flexible schedule with flextime and the option of working full remote or from our Barcelona office. Enjoy free Friday afternoons with a 7-hour workday, plus a 35-hour workweek in July and August so you can savor summer! Comprehensive benefits Competitive salary, full-time permanent contract, and top-tier private health insurance (including dental and psychological services). 25 days of vacation plus your birthday off, with flexible vacation options—no blackout days! Unique Perks If you wish to come, in our office in Barcelona you’ll find it complete with free coffee, fresh fruit, snacks, a game room, and a rooftop terrace with stunning Mediterranean views. Additional benefits include ticket restaurant and nursery vouchers, paid directly from your gross salary. Join us in an environment where you’re free to innovate, learn, and grow alongside passionate professionals. You’ll tackle exciting challenges and be part of a vibrant team dedicated to delivering exceptional user experiences Equal Employment Opportunity Employer Our company is an Equal Employment Opportunity (EEO) Employer, which means we encourage applications from people with different backgrounds, interests, and personal circumstances. Our team welcomes applicants regardless of their race, gender, age, religion, nationality, sexual orientation, and/or disabilities. All we need is your high energy, skills, and willingness to be part of a great project! Location You'll have the flexibility to choose whether you'd like to come to the office every day, from time to time, or work fully remote. We want you to find the best combination for you. If you prefer to be surrounded with amazing people, our exceptional office is in Barcelona's Blue Building, located right on the city's seafront. Besides our stunning views, you'll enjoy our office perks such as free fruit, snacks, and coffee and you'll also be able to take part in our Mario Kart and table tennis competitions. The personal data you provide will be used to manage your candidacy for the corporate selection processes that fit your profile. If you wish, you can exercise your rights of access, rectification or cancellation by sending a letter to Avenida Litoral, 12-14, 5ta planta, Barcelona 08005, or emailing us at [email protected], including a document that validates your identity.