Backend Engineer

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 IAM & BILLING AT LANGFUSE

Your work will be the foundation everything else is built on.

Every API call, every dashboard load, every team invitation, every usage-based invoice — they all flow through the systems you'll own. Authentication, authorization, and billing aren't features at Langfuse; they're the shared platform that every product team depends on.

This is a role with unusual scope. You'll design the identity and access model that lets Fortune 50 companies manage hundreds of users across projects and environments with fine-grained permissions. You...