Düsseldorf | €80.000 - 95.000 | hybrid | permanentYOUR MISSIONAs a Senior Fullstack Engineer, you are a core builder in our Research and Development initiative: an AI platform that automates security reviews at the architecture level. You spend most of your time on the backend – building AI-integrated services, async pipelines, and the APIs that power our research platform. You also build the surfaces through which our consultants work with AI output, turning probabilistic results into something people can genuinely trust.YOUR ROLEBackend & API: Build and extend FastAPI endpoints, Celery task orchestration, PostgreSQL schemas, and GCS object storage; clean integration with the AI/ML pipeline.Data Flow Ownership: Design how the platform's data is stored, versioned, and served to the UI.Knowledge Approval Workflow: Design and extend the lifecycle layer for documents in the platform: data model, SLA tracking, escalation signals, and provenance metadata.Consultant-facing UI: Build the surfaces where AI output meets users: long running task UX, real time updates, and the path from polling to WebSocket/SSE streaming.End-to-End Delivery: Work with the AI team and an external UX designer to ship features from pipeline to UI – and own what works under the hood.Platform Reliability: Shape test strategies, structured logging, performance budgets, and the SDLC and agile practices the team needs as it grows.YOUR PROFILEMust haves5+ years of fullstack experience with production ownership of complex software – ideally including AI-integrated workflowsPython and FastAPI at senior level: API design, request validation with Pydantic, structured errorr handlingPostgresSQL: schema design, migrations, query optimizations, audit and versioning patternsAsync at scale: streaming responses (SSE/WebSocket), bounded concurrency, retry strategy across nested boundaries, idempotent task design with Celery or equivalentReact and TypeScript: state management (TanStack Query, Zustand or similar), data-driven UI for domain expertsProduction deployment: Docker, Kubernetes or equivalent, CI/CD, and observability tooling (Sentry, OpenTelemetry or similar)Product judgement: you know what fits the roadmap and you speak up when something doesn'tExperience building SDLC and agile practices in a small teamStrong English communicationA real plusGCP experience: Cloud Run, GCS, Secret Manager, Vertex AIVector search (Weaviate, pgvector or similar) or graph databases (Neo4j or similar)AI/LLM systems: eval frameworks, prompt versioning, regression on non-deterministic outputsSecurity engineering: authn/authz patterns, session management, secrets handlingTest strategy: experience building testing practices systematically within a teamBackground in developer tools, data-heavy SaaS, or expert-facing productsWHY CLOUDYRIONWe support EU Blue Card sponsorship and offer a relocation package for international hires30 days of vacation plus additional days off on Christmas, New Year’s Eve, and your birthdayHybrid work with two remote days per week, trust-based working hours and the opportunity of Workations in any EU countryIndividual learning and development opportunities, including full coverage of advanced trainings, certification costs, and educational leave for exam daysIn-house gym, massage chairs, gaming area, and dedicated break spacesRegular team events and plenty of space for real collaborationABOUT CLOUDYRIONCLOUDYRION was founded in 2020, bootstrapped and built around a simple idea: cybersecurity done properly, by people who actually care.We work with large enterprises in the telecoms, banking, insurance, automotive and critical infrastructure sectors. Our Secure by Design, Ethical Hacking and Secure Strategy Consulting services help them get security right from the ground up.With our founder as CEO and free from investor influence, we are still upholding our values five years on: Fail fast and learn quickly. Be a ray of sunshine. Tear down those walls.Working at CLOUDYRION means being part of a team who love what they do, embrace diversity and celebrate their successes together.This approach has proven its worth: our team now consists of 35 people and generates an annual turnover of around €6 million.Learn moreInsights from real-world projects, technical deep dives and our take on secure-by-design, cloud security and modern security architectures can be found on our blog.Authentic insights into our office life can be found on Instagram.Let’s talk! Do you feel inspired to take your next step? Then we look forward to your application. Whether classic or creative is up to you. What matters most is that you show us what drives you.Contact:Katharina - People & Culture📩 career@cloudyrion.com📞 +49 173 633 3724You can find information on data protection during the application process at CLOUDYRION here.