About the RoleA Y Combinator-backed AI creative tools startup is hiring its
founding software engineer. You'll work directly with the founding team to shape the technical foundation of an AI-powered motion design platform - turning what once took hours into minutes for professionals and video teams worldwide. This is a high-ownership, zero-to-one role at a company with strong early traction and rapid revenue growth.
What You'll Do- Partner with the founders to deliver user-centric product features from concept to production.
- Own end-to-end full-stack development with a focus on scalable architecture.
- Build and optimize agentic LLM systems, including tool-calling, multi-step reasoning, and MCP protocols.
- Design and implement comprehensive LLM evaluation frameworks - 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 to support growth to millions of users.
What We're Looking ForRequired:- 2+ years of software engineering experience with strong CS fundamentals.
- Proficiency in TypeScript (dealbreaker); hands-on experience with React.js, Next.js, PostgreSQL, GCP, and/or AWS.
- Proven experience building or integrating LLMs - tool-calling, multi-step reasoning, and MCP protocols.
- Experience designing LLM evaluation frameworks with automated benchmarks, human-in-the-loop validation, and A/B testing.
- Demonstrated ability to deliver end-to-end full-stack features at scale.
- Background in startups or early-stage environments with a strong ownership mindset.
- Ability to optimize LLM inference for performance, cost, and latency across multiple model architectures.
Nice to Have:- Experience in AI creative tools, motion graphics, or animation-adjacent products.
- High learning velocity and ability to ramp quickly in a fast-moving environment.
Compensation & Benefits- Salary: €80,000 - €160,000 annually, depending on experience.
- Equity participation as a founding team member.
- No visa sponsorship available.
LocationThis role is
on-site in Berlin, Germany. Candidates must be willing and able to work from the Berlin office full-time.
