Senior Software Engineer (SDK)

Senior Software Engineer for SDKs at Langfuse, an open-source LLM engineering platform now part of ClickHouse, building SDKs in Python and TypeScript for tracing and observability of AI applications.

• Owning our SDKs (Python and TypeScript) built on OpenTelemetry
• Ensuring reliability, performance, and developer experience of SDKs
• Designing APIs that developers love
• Integrating with every major AI framework (OpenAI SDK, Vercel AI SDK, LangChain, LlamaIndex, etc.)
• Maintaining our OpenTelemetry endpoint for users sending traces directly
• Writing public documentation for SDKs and integrations

• Strong engineer who gets excited about developer experience, API design, and writing code that runs reliably in other people's production systems
• Experience building or maintaining SDKs, client libraries, or developer tools — ideally in Python and/or TypeScript
• Deep understanding of performance: you know how to profile, benchmark, and minimize CPU/memory overhead in hot paths
• Someone who can manage projects themselves
• Thoughtful about versioning, backwards compatibility, and migration paths
• Interest in open source software and genuine excitement about talking to developers about their integration challenges
• Thrives in a small, accountable team where your output is visible and matters
• CS or quantitative degree preferred
• Bonus: Experience with OpenTelemetry internals or observability instrumentation
• Bonus: Former founder or early startup experience
• Bonus: Contributions to popular open source SDKs or developer tools
• Bonus: ML/AI background or familiarity with the LLM framework ecosystem