(Senior) Product Engineer

In Short: We're looking for an experienced product engineer to help us scale our platform as we grow.
About Langfuse

• We are building the fastest growing open-source LLM engineering platform . We help engineers and enterprises build and run LLM applications at scale.
• We've raised $4m from Y Combinator, Lightspeed and General Catalyst.
• Thousands of teams and engineers use Langfuse daily. Thousands are joining every month.
• We're a small, focused team working in-person from Berlin, Germany.

What you'll do

• Scale our platform to handle billions of events per day via our SDKs
• Optimize complex database queries in Postgres and Clickhouse
• Build and maintain async workflows and background processing
• Help customers deploy Langfuse in self-hosted environments
• Write infrastructure code and manage scaling with custom metrics
• Work on our Python and TypeScript SDKs

Tech

• Frontend and Backend in Typescript (including Express, NextJs, Tailwind, Prisma, tRPC)
• Clickhouse, Postgres, Redis, S3
• Client facing SDKs in Python and Typescript
• You should be familiar with a majority of these but we trust that you can pick up a new language/framework quickly.

What we're looking for

• 3+ years backend or full-stack development experience
• Experience building highly reliable, scaling infrastructure
• Interest in open source software and talking to users
• Hard worker who thrives in a small, accountable team
• CS or quantitative degree preferred
• Impressive achievements (professional or otherwise)

Bonus points:

• Former founder
• Experience in SDK design
• DX, ML/AI background

Why Langfuse?

• Building for very sophisticated technical users
• Competitive salary & equity compensation
• Strong customer & revenue growth
• You are still joining really early
• Strong in person engineering culture (Berlin-Mitte)
• Extreme autonomy
• Performance and learning focused culture
• Everyone on the team says: "best place I've ever worked at"
• 2 short scheduled meetings per week

Process
We can run this process to offer in less than 7 days.

1. Fill out application
2. We screen your application
3. Jump on a intro call with our CTO
4. Technical Deep Dive interview (90min)
5. Super Day ( half or full day in Berlin Office)
6. Meet the other founders (short calls)
7. Decision & Offer

Links

• Project you could have built: Infrastructure Evolution Blog Post
• Our codebase: GitHub Repository
• Ben Kuhn on Impact, Agency and Taste
• Who we are & how we work
• What is a Product Engineer (PostHog)

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