Senior Software Engineer (SDK)
Langfuse · Europe
ABOUT LANGFUSE Open Source LLM Engineering Platform that helps teams build useful AI applications via tracing, evaluation, and prompt management (mission https://tracking.us.nylas.com/l/6d586a21a6fc4e1a8aacc7eb75882b72/0/82383757e54352130f65066e1b2fc4708aacab7897561bcb8000fe4c8a9c6a21?cache_buster=1761124921, product https://tracking.us.nylas.com/l/6d586a21a6fc4e1a8aacc7eb75882b72/1/b9fba3a93b6ffcc0f99ecda62767a17cc437fe8fe0b16181d1c43c1391212e3d?cache_buster=1761124921). We are now part of ClickHouse. We're building the "Datadog" of this category; model capabilities continue to improve, but building useful applications is really hard, both in startups and enterprises. Largest open source solution in this category: trusted by 19 of the Fortune 50, >2k customers, >26M monthly SDK downloads, >6M Docker pulls. We joined ClickHouse in January 2026 because LLM observability is fundamentally a data problem and Langfuse already ran on ClickHouse. Together we can move faster on product while staying true to open source and self-hosting, and join forces on GTM and sales to accelerate revenue. Previously backed by Y Combinator, Lightspeed, and General Catalyst. We're a small, engineering-heavy, and experienced team in Berlin and San Francisco. We are also hiring for engineering in EU timezones and expect one week per month in our Berlin office (how we work https://langfuse.com/handbook/how-we-work/principles). WHY SDK ENGINEERING AT LANGFUSE YOUR WORK WILL HAVE AN OUTSIZED IMPACT. Our SDKs are downloaded 26M+ times per month. When you ship a new integration or improve SDK performance, thousands of developers benefit the same day — and they'll tell you about it in GitHub issues, on Twitter, and in our community channels. Everything you build is open source (MIT-licensed) and immediately visible. The SDK is often the very first thing a developer touches when they try Langfuse, so your work directly shapes their first impression. You will also have direct exposure