Full Stack Engineer (Senior) - Frankfurt

An exciting opportunity for an experienced FullStack Engineer to join a growing AI StartUps, where you will help build and maintain a high-performance, real-time, server-rendered web application.

Responsibilities:

• Real-Time Engine Architecture: Design and maintain resilient WebSocket communication pipelines - handling reconnection strategies, client-server state synchronization, concurrent task coordination, and message validation across boundaries.
• SSR & Hydration Engineering: Build server-side rendered interfaces with extreme care around hydration correctness, loader patterns, state rehydration, and explicit server-versus-client code splitting.
• Type Safety & Runtime Guardrails: Enforce end-to-end type safety using strict TypeScript on the client and runtime validation at all untrusted system boundaries (APIs, WebSockets, and state payloads).
• Containerized Deployment: Package, deploy, and monitor front-end and BFF microservices using Docker and Kubernetes.

Requirements:

• Advanced knowledge of asynchronous programming paradigms, Event Loops, WebSockets lifecycle management, client-side caching, and streaming state.
• Solid proficiency with Python async frameworks (FastAPI, WebSockets, asyncio) to build and maintain robust backend-for-frontend layers.
• Dedication to rigorous testing (Jest, React Testing Library, Playwright/Cypress) and clean code hygiene (conventional commits, static analysis, CI/CD pipelines).
• Practical experience containerizing front-end applications, managing multi-stage Docker builds, and deploying workloads on Kubernetes.

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