Senior Full-Stack Developer - Internal AI Platform and Productivity Apps (m/f/d)

We are looking for people who are passionate about technology and are excited to create the best experience for our customers. People who want to make an impact. We are looking for people like you. Let's Go!Your TasksWe’re looking for a Senior Full‑Stack Developer to design and build modern web applications, process automations and an internal AI platform serving 55,000 employees. You will participate in architecture decisions, lead external and nearshore teams, and partner with stakeholders to ship secure, scalable products that boost enterprise productivity.Responsibilities:Design, build, and operate full‑stack applications using Node.js, TypeScript, React,n8n,power platformDevelop robust APIs and microservices (Node.js/TypeScript, REST/GraphQL), including authentication/authorization, rate limiting, and observabilityPartner in the evolution of our internal AI platform: integrate LLMs and vector search, build reusable AI services and deliver employee‑facing AI tools.Define reference architectures, coding standards, and reusable component libraries; champion performance, accessibility, and security by designOwn CI/CD and DevOps workflows (GitHub Actions/Azure DevOps, Docker, Kubernetes); automate testing and deployments; establish blue/green or canary releasesCoordinate and quality‑assure external vendors and development partners; plan sprints, review deliverables, and ensure on‑time, on‑budget outcomesCollaborate with product and business stakeholders to translate needs into clear technical roadmaps, user stories, and measurable outcomesEnforce engineering excellence through code reviews, automated tests (unit/integration/e2e), and monitoring/alerting (OpenTelemetry/Prometheus/Grafana)Apply secure engineering practices (OWASP, secrets management, least privilege), data privacy, and compliance requirementsYour Profile6+ years of software engineering with a focus on full‑stack web developmentAdvanced proficiency in Node.js, TypeScript, React, and modern front‑end tooling .Strong back‑end skills: API design, microservices, relational and NoSQL databases, caching (Redis)Hands‑on experience with cloud‑native delivery: containers (Docker), orchestration (Kubernetes), CI/CD, and infrastructure as code (Terraform or Pulumi)Excellent communication, stakeholder management, and mentoring skillsReadiness to learn new technologiesPassion for new and upcoming tech trendsPreferred:Experience in RAD tools(powerplatform,n8n,K2 etc)Experience building AI‑powered applications: integrating LLMs (OpenAI/Azure OpenAI, etc.), vector databases (Pinecone/pgvector/Elasticsearch), embeddings, and RAG patternsKnowledge of identity and access management (OIDC/OAuth 2.0, SSO), API gateways, and zero‑trust patternsObservability and reliability engineering (SLOs, error budgets, chaos testing)Experience with performance optimization at scale (web vitals, SSR/SSG, CDN, edge runtimes)Familiarity with Microsoft ecosystem and M365 (Entra ID/Azure) for integration in a large enterpriseWhat's in it for you?Young environment, where not everything is written in stone, and where you are expected to contribute and co-create the culture of the Tech Hub and international collaboration modelYou'll have a 10% discount on the entire MediaMarkt website, so you can treat yourself at a lower price whenever you want!On top of your compensation package, you can request Flexible Pay “MediaFlex program” (a.e. Ticket Restaurant, Private Health Insurance)Flexible working time and possibility to combine home office / presential working. Intensive workday every Friday and during summerThe possibility to choose between 2 offices: The first one is the MediaMarkt Spain HQ with a very attractive menu at a price. You'll eat for less than €4! And the second office is located at Pier01, in Barceloneta, right in the center of Barcelona. Free coffee and free fruit once a weekIf you need a VISA, don't worry, we'll assist you with the visa process and accompany you throughout the entire process!There is a training budget so you can continue developing the skills you need most to keep growing professionally and personally!We offer language classes: English, Spanish, and GermanOn your birthday, you won't work! It's a day for you to enjoy without thinking about workYou'll be working with the most cutting-edge technological stack of the momentTraining planFlexible working schedule, home office policyGymProduct discountsWellness and healty plansMedia Flex, flexible retributionAbout UsMediaMarktSaturn is Europe’s leading consumer electronics retailer. It sees itself as a partner, daily companion and navigator for its customers in the digital world. Its over 1,000 MediaMarkt and Saturn stores are closely integrated with their online shops. MediaMarktSaturn has a total headcount of more than 60,000.MediaMarktSaturn Technology is working on making Europe's number one consumer electronics retailer the technology leader in its sector. To this end, several hundred developers, UX designers and system architects using state-of-the-art technology work hand in hand with business owners in agile teams to develop customer-focused technology solutions for more than 6 million customers every day in 11 countries.Technology Hub located in Barcelona, is one of the service units of MediaMarktSaturn Technology to deliver adequate staffing and engineering skills for the agreed deliveries of the global deployment plan for the entire group.Modern Workplace at MediaMarkt Saturn is seeking a skilled M365 Power Platform Developer to enhance our digital processes across offices and stores, improving the overall digital workplace experience for all employees.