Founding Software Engineer

About the Role

This is a rare opportunity to join a fast-growing, Y Combinator-backed AI SaaS startup in the motion design space as its first engineering hire. The company is building an AI-powered platform that dramatically accelerates animation creation - reducing what once took hours into minutes - and has already seen remarkable early traction since launching earlier this year.

As a Founding Software Engineer, you'll work shoulder-to-shoulder with the founders to shape the technical foundation of the product, own features end-to-end, and help architect a system built to scale to millions of users.
What You'll Do

• Partner directly with the founding team to deliver user-centric product solutions from concept to production.
• Own end-to-end development of full-stack features with a focus on scalable architecture design.
• Build and optimize agentic LLM systems incorporating tool-calling, multi-step reasoning, and MCP protocols.
• Design comprehensive LLM evaluation frameworks including 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.

What We're Looking For

Required

• 2+ years of software engineering experience with strong CS fundamentals.
• Proficiency in TypeScript (dealbreaker requirement).
• Hands-on experience building or integrating large language models (LLMs), including tool-calling, multi-step reasoning, and MCP protocols.
• Experience designing and implementing LLM evaluation frameworks (automated benchmarks, human-in-the-loop validation, A/B testing).
• Demonstrated ability to deliver end-to-end full-stack features with scalable architecture.
• Proficiency optimizing LLM inference performance, cost efficiency, and latency across multiple model architectures.
• Experience with the full tech stack: TypeScript, React.js, Next.js, PostgreSQL, GCP, AWS.
• Prior startup or early-stage company experience with a strong ownership mindset.
• Willingness to work on-site in Berlin, Germany.

Nice to Have

• Background in animation, motion graphics, or creative tooling.
• High slope / fast-learning profile with a track record of rapid growth.

Compensation & Benefits

• Salary: €80,000 - €160,000 per year, depending on experience.
• Early-stage equity opportunity as the founding engineering hire.
• Visa sponsorship: Not available - candidates must already have the right to work in Germany.

Location

• Berlin, Germany - fully on-site role.
• Remote work is not available for this position.