(Senior) Backend Engineer

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.

• 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.

1. Fill out application

2. We screen your application

3. Jump on a intro call with our CTO

4. Technical Deep Dive interview

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

Compensation: €70K – €160K • + Equity Package

• • Base Salary + Equity €70K – €160K • + Equity Package