Senior Fullstack Engineer, AI Observability & Evals

LangChain is seeking a Senior Fullstack Engineer for LangSmith to shape the technical direction of our observability and evals platform, collaborating with enterprise customers and internal stakeholders. You will own critical features across Go, Python, and TypeScript and mentor teammates. The role emphasizes API design, scalable architectures, and delivering high-quality, maintainable code in a fast-paced environment. Salary and equity reflect seniority in a US-based product team.