In short: We are hiring a (senior) Backend Engineer to make our systems and infra keep up with our globally growing user base and billions of monthly events to process.

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 from Berlin, Germany.

What you'll do

Past projects you would have led:

Optimizing the latency of complex database queries in Postgres or Clickhouse
Adding Redis queues and a worker container to our stack to execute async tasks
Come up with a new architecture for our ingestion pipeline with the goal to increase throughput and cut cost
Explore different CH schemas and materialized views and test for different query patterns.
Re-building our SDKs to use OTEL under the hood
Write Terraform code to add new infra components

Tech Stack

You should be familiar with a majority of these but we trust that you can pick up a new language/framework quickly.

Frontend and Backend in Typescript (including Express, NextJs, Tailwind, Prisma, tRPC)
Clickhouse, Postgres, Redis, S3
Client facing SDKs in Python and Typescript

What we're looking for

Experience in maintenance of highly reliable and scaling infrastructure
3+ years of experience in backend or full-stack development
Excited about open source software
Experience with the trade offs of handling large amounts of data
Hard worker and thrive working in a small and accountable team
A CS/quantitative degree is preferred

Bonus

Experience with or interest in SDK design and DX
ML/AI experience
Impressive achievements from previous careers or side projects
Previous startup or founding experience

Why Langfuse?

You are joining really early
Strong Product Market Fit!
We are building a very small but highly capable team
Only hiring Engineering in foreseeable future
Strong customer & revenue growth
Building picks and shovels for the hottest AI companies
Building for very sophisticated technical users
Competitive salary & equity
Performance and learning focused culture
Everyone on the team says: "best place I've ever worked at"

How we work

Engineering based in Berlin ( we aim for 4-5 days in the office )
No more than 2 short scheduled meetings per week
Extreme ownership & autonomy how and what to work on

Hiring Process

We can run this process in less than 7 days.

Fill out application
We screen your application
Jump on a intro call with our CTO
Technical Deep Dive interview
Super Day ( half or full day in Berlin Office )
Meet the other founders (short calls)
Decision & Offer