Senior Fullstack Engineer

ABOUT THE ROLE We are an angel-backed AI SaaS startup building a German-language AI phone assistant used by thousands of European businesses. Our small, high-growth team operates in a remote-first environment with strong CET overlap, and we are looking for a Senior Fullstack Engineer who thrives on end-to-end ownership — from idea through architecture, implementation, and release. This role sits at the intersection of engineering and product: you will engage directly with customers, run experiments, and ship features that deliver measurable value. Native-level German proficiency is required, as our product and many of our customers operate in German. WHAT YOU'LL DO - Own features end-to-end — from prototype and architecture decisions through to customer-facing release. - Engage continuously with customers, partners, and the sales team to surface real pain points and translate them into product improvements. - Run product discovery by forming hypotheses and validating them with lightweight experiments before building large systems. - Instrument and track the metrics relevant to your area to enable data-driven decisions. - Build pragmatic, scalable software that balances immediate customer value with long-term maintainability. - Communicate asynchronously where possible and prioritize shipping over excessive process. - Act with radical ownership — push initiatives forward without waiting for permission. - Work remotely with CET overlap, or from the Vienna office as needed. WHAT WE'RE LOOKING FOR - 5+ years of full-stack engineering experience delivering end-to-end web features. - Strong proficiency in Node.js, TypeScript, NestJS, and React. - Native-level German proficiency — non-negotiable for this role. - Product mindset: you measure success by customer value, not lines of code. - Experience with product discovery — forming hypotheses and validating them quickly through experiments. - Comfortable owning analytics, tracking, and data to support product decisions. - Experience collaborating directly with customers, partners, and sales to define value and understand pain points. - Strong CS fundamentals and sound judgment on effort/quality/speed trade-offs. Nice to have: - Experience integrating LLMs (e.g., OpenAI) into production applications — a significant plus. - Experience deploying AI-enabled services on Microsoft Azure in Europe. - Familiarity with GDPR and EU AI Act considerations for AI services. - Prior experience in a high-growth startup environment. COMPENSATION & BENEFITS - Salary: $80,000 – $120,000 USD annually (or equivalent), depending on experience. - Remote-first culture with strong async communication norms. - Small, high-ownership team where your impact is visible and meaningful. LOCATION Fully remote with CET timezone overlap preferred. The team is headquartered in Vienna, Austria; occasional in-office collaboration is possible. Visa sponsorship is not available — candidates must already have the right to work in the relevant jurisdiction.