Senior Fullstack Engineer

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., * 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.

• 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.

• 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.

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., 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.