Founding Software Engineer

• Partner with founders to deliver user-centric product solutions from concept to production.
• Own end-to-end development of full-stack features with scalable architecture design.
• Build and optimize agentic LLM systems incorporating tool-calling, multi-step reasoning, and MCP protocols.
• Design comprehensive LLM evaluation frameworks with automated benchmarks, human-in-the-loop validation, and A/B testing.
• Optimize LLM inference performance, cost efficiency, and latency across multiple model architectures.
• Develop a high-performance motion graphics engine.
• Drive architectural decisions that support scalable growth to millions of users.

Do you have experience in TypeScript?, Do you have a Master’s degree?, * 2+ years of software engineering experience with strong CS fundamentals.

• Proficiency in TypeScript (required) and ideally the broader stack: React.js, Next.js, PostgreSQL, GCP, AWS.
• Hands-on experience building or integrating LLMs, tool-calling, multi-step reasoning, and MCP protocols.
• Experience designing and implementing LLM evaluation frameworks - automated benchmarks, human-in-the-loop validation, and A/B testing.
• Proven ability to deliver end-to-end full-stack features with scalable architecture.
• Startup or early-stage company experience with a strong ownership mindset.
• Proficiency in optimizing LLM inference performance, cost efficiency, and latency across multiple model architectures.

Salary range: €80,000 - €160,000 EUR annually, depending on experience. As an early founding engineer, you can expect meaningful equity alongside your base compensation.

Join a Y Combinator-backed AI SaaS startup as their first engineering hire. The company is building an AI-powered motion design product that turns hours of animation work into minutes - already serving a rapidly growing user base. You’ll work directly with the founders to shape the technical foundation, own end-to-end development, and help scale the product to millions of users.