Senior Fullstack Engineer

Senior Fullstack Engineer for a seed-funded European AI voice technology startup. Own end-to-end features from prototype to production for a German-language AI phone assistant used across Europe. Responsibilities include architecture, implementation, product discovery, customer engagement, instrumenting metrics, and balancing short-term value with long-term maintainability. Requirements: 5+ years fullstack experience, strong hands-on Node.js, TypeScript, NestJS, and React, native-level German, fluent English, experience with product discovery and metrics. LLM/OpenAI integration, GDPR and EU AI Act familiarity, and startup experience are pluses. Visa sponsorship not available.