Product Engineer

Langfuse is building open source dev tooling for LLM apps based on observability/tracing. We have significant traction, are growing fast. We are looking for a full stack product engineer to help us build out our platform in Berlin, Germany.

About Langfuse: Langfuse is building the open-source LLM engineering platform. We help engineers understand how users interact with their LLM applications and how they can improve them. We have raised a $4m seed round from Y Combinator, Lightspeed and General Catalyst. Thousands of engineers use Langfuse to observe, debug and improve their LLM apps.

What you will be working on: Your main responsibility will be to add new features and build out existing ones in Langfuse. At the core of Langfuse lies the ingestion of millions of events a day via our SDKs. Once the data is in our database, we visualize it in our UI and run async workflows on top of it in the background.

Projects you would be involved in:

• Our first launch week
• The build out of our model-based evals feature
• Rolling out the LLM Playground and connecting it to other parts of the product
• Maintaining our core integrations and introducing new ones

Stack: Frontend and Backend in Typescript (T3 Stack including NextJs, Tailwind, Prisma, tRPC), Clickhouse, Postgres, Client facing SDKs in Python and Typescript.

The opportunity: You are joining Langfuse early. We will treat you as a core member of the team from day 1 and you will be incentivized as such. Your decisions and code lie at the foundation of our product. You will contribute to a thriving commercial open source project and build in public. You will own parts of the Langfuse product end-to-end.

Who We Are Looking For:

• Hard worker who thrives in a small and accountable team
• Wants to take ownership in shipping features for a fast growing devtool
• Excited about open source software
• 2+ years of experience in full-stack development
• Impressive achievements from previous careers and side projects

Bonus Points:

• Experience with or interest in UX/UI design and DX
• Started a company before or worked at a very early stage startup
• ML/AI experience

Team, Values & Benefits: We work in-person from our office in Berlin-Mitte. We aim for 3-5 days in the office a week. Our team culture is built around performance and learning. We want to build a small team of highly motivated, independent and intelligent people.