Principal Software Engineer, AI Observability & Evals Platform

Principal engineering on LangSmith, which the posting describes as LangChain's core platform for observability, evaluation and production reliability of AI systems — tracing through to evals. The role is framed around how the product lands rather than how the code reads, so it carries product judgement alongside the systems work. Database and cloud experience is listed as a nice-to-have; the team sits alongside the open source frameworks rather than inside them.