Senior Software Engineer – Fullstack

Luzia; Madrid; Presencial; EUR 45.000 - 70.000; Jornada completa

Descripción de la vacante

Luzia, based in Madrid, is seeking an experienced software engineer to build engaging AI product experiences. You will work across the stack, developing both backend services in Python and frontends with TypeScript and Next.js, while collaborating with AI engineers and product managers.

The ideal candidate has over 5 years of experience in software engineering, with a strong focus on usability and performance. This hybrid role requires a passion for AI and innovative software development.

Formación

• 5+ years of experience as a software engineer building production systems.
• Strong backend experience in Python.
• Strong frontend experience in TypeScript and Next.js.
• Experience with AI-powered features in consumer products.

Responsabilidades

• Build magical AI product experiences.
• Ship across the stack and maintain backend services.
• Architect scalable backend systems.
• Collaborate with cross-functional teams.
• Write clean and maintainable code.

Conocimientos

Backend experience in Python

Frontend experience in TypeScript

Building AI agents

Product intuition

Ownership mindset

Curiosity across the stack

Descripción del empleo

What You’ll Do

• Build magical AI product experiences – Design and implement fast, intuitive, and engaging experiences that make AI feel natural and useful. Work closely with product and design to explore new interaction patterns, prototype ideas quickly, and turn cutting‑edge AI capabilities into simple experiences that millions of users enjoy.
• Ship across the stack – Build and maintain backend services in Python and production‑grade frontends in TypeScript and Next.js. Move fluidly between layers, owning features end to end.
• Architect scalable backend systems – Design and maintain backend services and APIs that power real‑time AI interactions at scale. Ensure performance, reliability, and cost‑efficiency as we grow rapidly across markets.
• Move fast, ship often – Operate with high ownership and urgency. Prototype quickly, validate with users, and iterate based on real‑world feedback. Use modern AI‑assisted development tools to accelerate development cycles while maintaining strong engineering quality.
• Collaborate across AI, product & growth – Work cross‑functionally with AI engineers, product managers, designers, and growth teams to translate experimentation and insights into production‑ready systems.
• Raise the technical bar – Write clean, maintainable, well‑tested code. Contribute to architecture decisions, improve developer experience, and help establish best practices that enable the team to scale.
• Think in systems, not just tickets – Anticipate bottlenecks before they happen – whether in performance, UX, cost, or scalability. Proactively improve observability, reliability, and infrastructure as we scale.
• Mentor & lead by example – Provide thoughtful code reviews, support other engineers, and help shape a strong engineering culture centered around ownership, craftsmanship, and impact.

What We’re Looking For

• +5 years of experience as a software engineer building and shipping production systems used by real users
• Strong backend experience in Python
• Strong frontend experience in TypeScript and Next.js, with an eye for usability, performance, and interaction design
• Hands‑on experience building AI agents end‑to‑end – including tool use, orchestration, evaluation, and shipping them to production
• Experience building or integrating AI/LLM‑powered features in consumer‑facing products
• Curiosity about working across the stack, including backend services and APIs that power mobile experiences
• Comfort working in fast‑paced startup environments with ambiguity and rapid iteration
• Strong product intuition: you care deeply about how things feel for users, not just how they are implemented
• Experience building systems or applications used by large numbers of users
• Ownership mindset: you see problems, take initiative, and drive solutions end‑to‑end
• Interest in AI‑assisted software development, modern developer tooling, and experimenting with new ways of building products

Nice to have

• Experience with LangGraph and/or LangChain

Working model

This is a hybrid role based in our Madrid office – you’ll combine working from our office and working from home.

Equal opportunity

Luzia is an equal opportunity employer. We hire based on what you build and how you think.