Senior Fullstack Engineer

About the Role Join a fast-growing European AI voice tech company building an AI-powered phone assistant for small and medium-sized businesses. As a Senior Fullstack Engineer, you'll take end-to-end ownership of product features — from idea and prototype through architecture, implementation, and release — on a remote-first team with real customer impact. What You'll Do Own features across the full stack, from discovery and architecture to shipping and measuring outcomes. Engage directly with customers, partners, and Sales to surface real pain points and inform what gets built. Form hypotheses and validate them quickly through lightweight experiments before committing to large-scale solutions. Instrument features and gather metrics to enable data-driven product decisions. Build pragmatic, scalable software balancing immediate customer value with long-term maintainability. Communicate and collaborate asynchronously, prioritizing shipping over excessive meetings. Act with radical ownership — push initiatives forward without waiting for permission. What We're Looking For 5+ years of experience in fullstack engineering with end-to-end delivery responsibility for customer-facing applications. Strong hands-on experience with Node.js, TypeScript, NestJS, and React . Experience integrating LLMs (e.g., OpenAI) into production software applications — a significant plus. Product mindset: you measure success by customer value, not lines of code. Skilled at extracting actionable insights from direct conversations with users, partners, and sales teams. Comfortable owning analytics, tracking, and the data layer needed to support product decisions. Experience deploying AI-enabled services on cloud infrastructure in Europe (e.g., Microsoft Azure) is a bonus. Familiarity with GDPR and EU AI Act considerations for AI-powered services is a plus. Experience working in a high-growth startup environment. Strong CS fundamentals and sound judgment when trading off effort, quality, and speed. Native-level German proficiency is required — the product serves a German-language market. Compensation & Benefits Salary range: €80,000 – €120,000 annually. Visa sponsorship is not available. Location Fully remote, with a preference for candidates based in Germany or Austria (CET timezone overlap expected). Optional access to a Vienna office.