<h3>About the Role</h3><p style="min-height:1.5em">We're looking for a <strong>Senior Backend Engineer</strong> to own and scale the infrastructure behind one of the most widely adopted open-source LLM engineering platforms in the world — processing terabytes of AI tracing data per day for thousands of AI teams, including a significant portion of the Fortune 50.</p><p style="min-height:1.5em">We're a small, engineering-heavy team building what many consider the "Datadog" of LLM observability. We sit at the intersection of open source, high-throughput data infrastructure, and applied AI — and we're now part of a leading columnar database company, which means the engineers who built the database you'll be optimizing are a Slack message away.</p><p style="min-height:1.5em">This is a <strong>hybrid role</strong> based in EU timezones, with approximately <strong>one week per month</strong> in our Berlin office. You can be based anywhere in the EU. <em>Visa sponsorship is not available — you must be legally authorized to work in the EU.</em></p><h3>What You'll Do</h3><ul style="min-height:1.5em"><li><p style="min-height:1.5em"><strong>Own and optimize the ingestion pipeline:</strong> Work on throughput, latency, reliability, and cost efficiency across a high-volume data pipeline that flows from our API through to a ClickHouse-backed analytics store.</p></li><li><p style="min-height:1.5em"><strong>Make ClickHouse sing:</strong> Design and evolve schemas, write and tune complex analytical queries, and partner with ClickHouse engineers to push the limits of what's possible at petabyte scale.</p></li><li><p style="min-height:1.5em"><strong>Build backend abstractions:</strong> Create reusable, well-documented building blocks so that product engineers can ship data-heavy features without reinventing infrastructure each time.</p></li><li><p style="min-height:1.5em"><strong>Operate production systems:</strong> Run and improve cloud deployments across multiple production environments — handling capacity planning, incident response, and monitoring with SRE discipline.</p></li><li><p style="min-height:1.5em"><strong>Make self-hosting effortless:</strong> Maintain and improve deployment tooling from a single Docker Compose setup all the way to enterprise-grade Helm chart deployments on Kubernetes.</p></li><li><p style="min-height:1.5em"><strong>Contribute to open source:</strong> Everything you ship is public and immediately used by developers worldwide — participate in PR reviews, issue triage, and community engagement.</p></li></ul><h3>What We're Looking For</h3><p style="min-height:1.5em"><strong>Required:</strong></p><ul style="min-height:1.5em"><li><p style="min-height:1.5em">Based in the EU and able to work EU timezones; willing to be in Berlin approximately one week per month</p></li><li><p style="min-height:1.5em">Legally authorized to work in the EU without company visa sponsorship</p></li><li><p style="min-height:1.5em">Hands-on experience with <strong>C