Founding Software Engineer
On-site · Berlin, State of Berlin, Germany
Job Summary
Founding Software Engineer to partner with the founders to shape the technical foundation, own end-to-end development, and build a high-performance motion graphics engine. You’ll design scalable architectures, develop full-stack features, and implement agentic LLM systems with tool-calling and multi-step reasoning, plus design automated evaluation frameworks with benchmarks and A/B testing, while driving architectural decisions to support growth to millions of users. Must have strong CS fundamentals and hands-on experience with LLMs, tool-calling, multi-step reasoning, LLM evaluation frameworks, and the full stack (TypeScript, React.js, Next.js, PostgreSQL, GCP, AWS). Startup/early-stage ownership mindset required; in Berlin, Germany, office-based.
Required Qualifications
- Strong CS fundamentals
- Hands-on experience building or integrating large language models (LLMs)
- tool-calling
- multi-step reasoning
- MCP protocols
- Experience designing and implementing LLM evaluation frameworks with automated benchmarks
- human-in-the-loop validation
- A/B testing
- End-to-end full-stack feature delivery with scalable architecture
- Startup/early-stage company experience with ownership mindset
- Proficiency with TypeScript, React.js, Next.js, PostgreSQL, GCP, AWS
- Proficiency in optimizing LLM inference performance, cost efficiency, latency across multiple model architectures
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