Senior Backend Engineer

Details

Open Source LLM engineering platform (Langfuse, now part of ClickHouse) that helps teams build useful AI applications via tracing, evaluation, and prompt management. The team is engineering-heavy, distributed across Berlin and San Francisco, and is hiring for engineering in EU timezones. The role is hybrid with an expectation of roughly one week per month in the Berlin office.

Responsibilities

• Own and optimize the ingestion pipeline that moves tracing data from the API into ClickHouse: throughput, latency, reliability, and cost efficiency.
• Design ClickHouse schemas, optimize merge strategies, tune batch inserts, and write/ review analytical queries that power dashboards and UI components.
• Build infrastructure-heavy features (e.g., post-processing large volumes of ingested data, alerting at scale, client-code execution, batch dataset operations).
• Operate Langfuse Cloud across multiple production environments and make self-hosting effortless (support single Docker Compose setup through enterprise Helm chart deployment).
• Test with real production data: prototype new table designs, run parallel schemas on real traffic, and validate performance improvements.
• Think ahead to scale (10x) and plan infrastructure changes to support new product directions such as long-running agent observability and real-time evaluation.

Requirements

• Strong backend engineering experience with interest in database internals, query optimization, and distributed systems.
• Experience working with large volumes of data; familiarity with analytical databases, data pipelines, or high-throughput event processing. ClickHouse experience is a big plus but not required.
• Comfortable reading and writing TypeScript (backend) and SQL.
• Experience or familiarity with building and operating ingestion pipelines, schema design, and batching strategies.
• Ability to operate production services and support both cloud and self-hosted deployments (Docker Compose, Helm).
• Interest in open source software and engaging with users about scaling challenges.
• Strong organization and ownership; ability to propose solutions (RFCs) and ship them.
• CS or quantitative degree preferred.

Bonus

• Experience with ClickHouse, other OLAP databases, or observability infrastructure.
• Background in building data-intensive systems at scale.
• Former founder.

Tech Stack

• TypeScript monorepo (Next.js frontend, Express workers for background jobs)
• ClickHouse for tracing at scale; PostgreSQL for transactional data
• S3 for file storage, Redis for queues and caching
• Docker Compose for single-node/self-hosted setups and Helm charts for enterprise deployments

Process

• The company can complete the full hiring process to an offer in less than 7 days.

How We Ship

• Engineer-driven ownership model (RFCs, individual Linear management).
• Maker schedule and focussed meetings: short Monday check-ins and a weekly demo.
• Code reviews are used for mentorship and onboarding.
• Encouragement to experiment with AI tooling internally.

Why Langfuse (now part of ClickHouse)

• Work at the intersection of observability and LLM engineering, processing terabytes of tracing data per day for thousands of teams.
• Open-source-first company with a high degree of engineering visibility and impact.
• Close collaboration with the ClickHouse team, enabling deep access to database internals and performance tuning expertise.
• Opportunities to ship features end-to-end and be visible in changelogs and community launches.

Location & Office

• Hiring for EU timezones with hybrid expectation (approximately one week per month in Berlin). Secondary locations listed: Berlin, London, Munich, Paris, Zurich. The broader region is Europe.